Human Anatomy and Physiology Lecture Notes PDF

LECTURE NOTES For Nursing Students Human Anatomy and Physiology Nega Assefa Alemaya University Yosief Tsige...

LECTURE NOTES For Nursing Students Human Anatomy and Physiology Nega Assefa Alemaya University Yosief Tsige Jimma University In collaboration with the Ethiopia Public Health Training Initiative, The Carter Center, the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education 2003  Funded under USAID Cooperative Agreement No. 663-A-00-00-0358-00. Produced in collaboration with the Ethiopia Public Health Training Initiative, The Carter Center, the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education. Important Guidelines for Printing and Photocopying Limited permission is granted free of charge to print or photocopy all pages of this publication for educational, not-for-profit use by health care workers, students or faculty. All copies must retain all author credits and copyright notices included in the original document. Under no circumstances is it permissible to sell or distribute on a commercial basis, or to claim authorship of, copies of material reproduced from this publication. ©2003 by Nega Assefa and Yosief Tsige All rights reserved. Except as expressly provided above, no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the author or authors. This material is intended for educational use only by practicing health care workers or students and faculty in a health care field. Human Anatomy and Physiology Preface There is a shortage in Ethiopia of teaching / learning material in the area of anatomy and physicalogy for nurses. The Carter Center EPHTI appreciating the problem and promoted the development of this lecture note that could help both the teachers and students. Human anatomy and physiology is more than just interesting, it is fascinating. To help get the students and instructions involved in the study of this subject, a number of special features are incorporated throughout the lecture note. The lecture note provides a thorough review of human anatomy and physiology applicable to the nurses. It covers all body parts using a systemic approach. Each chapter is designed to aid effective student learning. Each chapter contains: - The Learning objectives: what the students are expected to accomplish upon completion of a particular chapter. - Key concepts: summary of selected key terms included in the chapter. - Illustrations: there will aid the students to achieve a better understanding of the subject matter. i Human Anatomy and Physiology - Review questions: a cross check to know if the students have come to grasp concepts stated in the chapter. We hope that you enjoy the lecture note of Human Anatomy and Physiology for nurses. Please let us know if you have any comments regarding this lecture note. ii Human Anatomy and Physiology Acknowledgments We are highly indebted to acknowledge the authors of the reference books we used in preparing this lecture note. We would like to extend our appreciation to the different professionals involved in reviewing this manuscript through its process specially Dr. Yamrot Kinfu, Head, Department of Anatomy, Medical Faculty, AAU. We are also grateful to The Carter Center EPHTI for facilitating the preparation of this lecture note. Our gratitude also goes to the assistance offered by Jimma and Alemaya Universities for facilitating the opportunities and resources utilized to develop the lecture note. iii Human Anatomy and Physiology Table of Contents Preface Acknowledgement Table of contents List of tables Abbreviations Introduction CHAPTER ONE – INTRODUCTION TO HUMAN ANATOMY AND PHYSIOLOGY CHAPTER TWO – CELL CHAPTER THREE – TISSUES AND MEMBRANE CHAPTER FOUR – THE INTEGUMENTARY SYSTEM CHAPTER FIVE – THE SKELETAL SYSTEM CHAPTER SIX – THE MUSCULAR SYSTEM CHAPTER SEVEN – THE NERVOUS SYSTEM CHAPTER EIGHT – THE ENDOCRINE SYSTEM CHAPTER NINE – CARDIOVASCULAR SYSTEM CHAPTER TEN – RESPIRATORY SYSTEM CHAPTER ELEVEN – DIGESTIVE SYSTEM CHAPTER TWELVE – THE URINARY SYSTEM CHAPTER THIRTEEN _ FLUID AND ELECTROLYTE BALANCE CHAPTER FOURTEEN – THE REPRODUCTIVE SYSTEM Glossary Answers to the study questions References iv Human Anatomy and Physiology List of Tables Table 1.1 Directional terms Table 5. 1 Comparison between bone and cartilage Table 5.2 Divisions of the adult skeleton (206 bones) Table 5.3 Descriptions and functions of Cranial Bones Table 5.4 Descriptions and Functions of Facial bones Table 5.5 Bones of the vertebral column (26 bones) Table 5.6 Upper extremity bones and their function Table 5.7 Bones of the lower extremity and their function Table 5.8 Classifications of joints Table 5.9 Various types of movements by synovial joint Table 6-1 Summary of events in the contraction of a muscle fiber Table 6-2 Head and neck muscles Table 6-3 Trunk muscles Table 6-4 Upper limb muscles Table 6-5 Lower limb muscles Table 7-1 Functions of Major Divisions of the Brain Table 7-2 Effects of the sympathetic and Parasympathetic Systems on Selected Organs Table 7-3 Special Sense Organs Table 9-1 The ABO Blood Group System Table 10-1 Breathing Volumes Table 11-1 Chemical Digestion Table 12.1 The main structural components of a nephron and their function. Table 14.1 The Menstrual Cycle Table 14.2 Summary of major reproduction hormones v Human Anatomy and Physiology Abbreviations Ach: Acetylcholine ACTH: Adrino Cortico Trophic Hormone ADH: Anti di Uretic Hormone ADP: Adenosine Di Phosphate ANS: Autonomic Nervous System ATP: Adenosine Tri Phosphate C: Cervical, cervical vertebrae, (C4 cervical vertebrae 4) cm: Centi meter CNS: Central Nervous System CRH: Corticotropin Releasing Hormone CSF: Cerebro Spinal Fluid DIT: Di Iodo Tyrosine DNA: Deoxyribo Nucleic Acid /d: Per day ECF: Extra Cellular Fluid ER: Endoplasmic Reticulum FSH: Follicular stimulating hormone g: Gram GHIH: Growth Hormone Inhibiting Hormone GHRH: Growth Hormone Releasing Hormone GI: Gastro Intestinal GnRH: Gondotrophin Releasing Hormone HCG: Human Chorionic Gonadotrophin hormone Hcl: Hydrochloric acid vi Human Anatomy and Physiology hGH: Human Growth Hormone ICSH: Interstitial Cell Stimulating Hormone IGF: Insulin like Growth Factors IUD: Intra Uterine Device L: Lumbar, lumbar vertebrae, (L3, lumbar vertebrae 3) l: liter LES: Lower esophageal sphincter LH: Leutinizing Hormone LPH: Lito tropin Hormone m: Meter MIT: Mono Iodo Tyrosine ml.: Mili liter mm: Milli meter P: Phosphate PBI: Protein Bound Iodine H P : Power of Hydrogen PIH: Prolactin Inhibiting Hormone PNS: Peripheral Servous System POMC: Pro-Opio Melano Cortin PRH: Prolactin Releasing Hormone PTH: Para Thyroid Hormone RNA: Ribo Neuclic Acid rRNA: Ribosomal Ribo Neuclic Acid T: Thoracic, thoracic vertebrae, (T1 thoracic vertebrae 1) T3: Tri iodo tyronin T4: Thyroxin 2 Human Anatomy and Physiology TGB: Tyro globulin TRH: Tyro tropin Releasing Hormone TSH: Thyroid Stimulating Hormone UV: Ultra Violet 3 Human Anatomy and Physiology Introduction The course human anatomy and physiology for nurses is designed to help student nurses learn and understand how the human body is organized and function. Equipping the student nurse with the knowledge of anatomy and physiology will further assist the student in understanding what happens and what to do when the body is injured, diseased or placed under stress. This teaching and learning material (lecture note) for nursing students at a diploma level is prepared in line with this concept. Therefore, the students are expected to achieve the following general educational objectives after completion of the course: - Understand and use anatomical terms. - Understand the function of the various organs and their relations with one another. - Know the location of each organ and the important anatomical land marks. - Know the normal structure of the human body in general. - Use the knowledge of anatomy and physiology in nursing practice. 1 Human Anatomy and Physiology CHAPTER ONE INTRODUCTION TO HUMAN ANATOMY AND PHYSIOLOGY Learning Objective At the end of this chapter, the students should be able to: - Define Anatomy and Physiology - Explain Homeostasis - Describe levels of structural organization of the human body - Discuss directional terms, anatomical position, planes and sections used in Anatomy. - Differentiate body cavities Selected Key terms The following terms are defined in the glossary: Anatomical position Body regions Anatomy Directional terms Appendicular skeleton Homeostasis Axial skeleton Physiology Body cavities Quadrants Body plane 2 Human Anatomy and Physiology 1.1 What are Anatomy and Physiology? Anatomy: the word anatomy is derived from a Greek word “Anatome” meaning to cut up. It is the study of structures that make up the body and how those structures relate with each other. The study of anatomy includes many sub specialties. These are Gross anatomy, Microscopic anatomy, Developmental anatomy and Embryology. Gross anatomy studies body structure with out microscope. Systemic anatomy studies functional relationships of organs within a system whereas Regional anatomy studies body part regionally. Both systemic and regional approaches may be used to study gross anatomy Microscopic anatomy (Histology) requires the use of microscope to study tissues that form the various organs of the body. Physiology: the word physiology derived from a Greek word for study of nature. It is the study of how the body and its part work or function. 3 Human Anatomy and Physiology Hence, Anatomy and physiology are studied together to give students a full appreciation and understanding of human body. Homeostasis When structure and function are coordinated the body achieves a relative stability of its internal environment called homeostasis / staying the same. Although the external environmental changes constantly, the internal environment of a healthy body remains the same with in normal limits. Under normal conditions, homeostasis is maintained by adaptive mechanisms ranging from control center in the brain to chemical substances called hormones that are secreted by various organs directly into the blood streams. Some of the functions controlled by homeostasis mechanisms are blood pressure, body temperature, breathing and heart rate. 1.2 Level of structural organization of the body The human body has different structural levels of organization, starting with atoms molecules and compounds and increasing in size and complexity to cells, tissues, organs and the systems that make up the complete organism. 4 Human Anatomy and Physiology Figure: 1.1 Levels of structural organization of the body (source: Elaine n. MARIEB, (2000), Essentials of human anatomy and physiology, Addison th welsey longman inc., San Francisco, 6 ed) Atoms molecules and compounds: - At its simplest level, the body is composed of atoms. The most common elements in living organism are carbon, hydrogen, oxygen, nitrogen phosphorus and sulfur. Atoms → Molecule → Compounds. 5 Human Anatomy and Physiology Cell: The smallest independent units of life. All life depends on the many chemical activities of cells. Some of the basic functions of cell are: growth, metabolism, irritability and reproduction. Tissue: tissue is made up of many similar cells that perform a specific function. The various tissues of the body are divided in to four groups. These are epithelial, connective, nervous and muscle tissue. Epithelial tissue: - Found in the outer layer of skin, lining of organs, blood and lymph vessels and body cavities. Connective tissue: - Connects and supports most part of the body. They constitute most part of skin, bone and tendons. Muscle tissue: - Produces movement through its ability to contract. This constitutes skeletal, smooth and cardiac muscles. Nerve tissue: - Found in the brain, spinal cord and nerves. It responds to various types of stimuli and transmits nerve impulses. Organ: - Is an integrated collection of two or more kinds of tissue that works together to perform specific function. For example: Stomach is made of all type of tissues 6 Human Anatomy and Physiology System: Is a group of organs that work together to perform major function. For example: Respiratory system contains several organs. Organism level: - The various organs of the body form the entire organism. 1.3 Anatomical Terminologies The language of anatomy will probably be unfamiliar to you at first. But once you have understood the basic word roots, combining word forms, prefixes and suffix you will find that anatomical terminologies are not as difficult as you first imagined. 1.3.1. Anatomical Position. Anatomical positions are universally accepted as the starting points for positional references to the body. In anatomical position the subject is standing erect and facing the observer, the feet are together, and the arms are hanging at the sides with the palms facing forward. 7 Human Anatomy and Physiology Figure 1.2 Relative directional terms of the body. (Source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw nd hill inc, New York, 2 ed, pp 15) 1.3.2 Relative Directional terms Standardized terms of reference are used when anatomists describe the location of the body part. Relative means the location of one part of the body is always described in relation to another part of the body. 8 Human Anatomy and Physiology Table: 1.1 Directional terms (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2nd ed, pp 15) Term Definition and example Superior (cranial) Toward the head. The leg is supper to the foot. Inferior (caudal) Toward the feet. The foot is inferior to the leg. Anterior (ventral) Toward the front part of the body. The nose is anterior to the ears. Posterior (dorsal) Towards the back of the body. The ears are posterior to the nose. Medial Towards the midline of the body. The nose is medial to the eyes. Lateral Away from the midline of the body. The eyes are lateral to the nose. Proximal Toward (nearer) the trunk of the body or the attached end of a limb. The shoulder is proximal to the wrist. Distal Away (farther) from the trunk of the body or the attached end of a limb. The wrist is distal to the forearm. Superficial Nearer the surface of the body. The ribs are superficial to the heart. Deep Farther from the surface of the body. The heart is deeper to the ribs. Peripheral Away from the central axis of the body. Peripheral nerves radiate away from the brain and spinal cord. 1.3.3. Body parts Regions The body can generally be described to have areas of: Axial body part: - It is the part of the body near the axis of the body. This includes head, neck, thorax (chest), abdomen, and pelvis. 9 Human Anatomy and Physiology Appendicular body part: - It is the part of the body out of the axis line. This includes the upper and lower extremities. It is customary to subdivide the abdominal area into nine regions or more easily in to four quadrants. Figure 1.3 Abdominal sub divisions (Source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New nd York, 2 ed, pp 17) 1.4 Body planes and sections Body planes are imaginary surfaces or planes lines that divide the body in to sections. This helps for further identification of specific areas. 10 Human Anatomy and Physiology Sagittal plane: - divides the body into right and left half. - Mid sagittal plane: - divides body into equal left and right halves. - Para sagittal plane: - divides body into unequal left and right Frontal plane: - divides the body into asymmetrical antererior and posterior sections. Transverse plane: - divides the body into upper and lower body section. Oblique plane: - divides the body obliquely into upper and lower section. 11 Human Anatomy and Physiology Figure 1.4 Body planes (Source: Carola, R., Harley,J.P., Noback R.C., nd (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2 ed, pp18) 12 Human Anatomy and Physiology 1.5 Body Cavities The cavities of the body house the internal organs, which commonly referred to as the viscera. The two main body cavities are the larger ventral (anterior) and the smaller, dorsal (posterior) body cavity. The ventral body cavity constitutes the thoracic cavity and the abdomino-pelvic body cavity. The Thoracic cavity houses lung and heart. It is protected by the rib cage & associated musculature and the sternum anteriorly. It consists of the right and left pleural cavities and mediastinum (the portion of tissues and organs that separates the left and right lung). Abdomino-pelvic Cavity extends from the diaphragm inferior to the floor of the pelvis. It is divided into superior abdominal and inferior pelvic cavity by imaginary line passing at upper pelvis. Abdominal cavity contains the stomach, intestine, liver, spleen and gallbladder. The pelvic cavity contains urinary bladder, rectum, and portions of the reproductive organs. 13 Human Anatomy and Physiology The dorsal body cavity: it constitutes the cephalic cavity containing brain and the vertebral canal containing the spinal cord. Figure: 1.5 Body cavities (Source: Memmler, Ruth Lundeen, Barbara Jansen Cohen and Dena Lin Wood (1996), The Human Body in Health and th Disease, 8 Ed, pp 9). 14 Human Anatomy and Physiology Review Questions 1. The anatomical term opposite to lateral is: - a) Proximal b) Distal c) Medial d) Superficial e) Caudal. 2. When structure and function coordinated the body gets a relative stability. This phenomenon is called: a) Anatomical integrity b) Physiological stablity c) Homeostasis d) Hemostasis e) Body stasis 3. Which of the following is not the correct description of anatomical position? a) Body facing forward b) Head turned to side c) Palms facing forward d) Body standing e) Feet together. 4. A plane that divided the body into anterior and posterior parts is: - a) Medial plane b) Coronal or frontal plane c) Sagital plane d) Transverse plane e) Oblique plane 5. The abdominal cavity contains the a) Heart and lung b) Reproductive organs and urinary bladder c) Liver, spleen and stomach d) Urinary bladder and lungs e) Testes and ovaries 15 Human Anatomy and Physiology CHAPTER TWO CELL Learning objective At the end of this chapter, the students should be able to: - Explain structure and characteristics of human cell - Describe movements of particles across cell membrane - Discuss organelles of human cell & their function - Explain abnormal cellular function (cancer) Selected Key terms: The following terms are defined in the glossary Active movement Cancer Cell Cell inclusion Cytoplasm Diffusion Organelle Osmosis Passive movement Plasma membrane 16 Human Anatomy and Physiology 2.1 Cell Cell is the basic living structural and functional unit of the body. Cytology: - It is a branch of science concerned with a study of cells Cell Theory explains about a) All living organisms are composed of cell and cell products. b) Cell is the basic unit of structure & function of all living organisms. c) All cells come from the division of pre existing cell. d) An organism as a whole can be understood through the collective activities & interactions of its cells. To know more about cell, we can divide the cell in to four principal parts: - Plasma (cell) membrane: it is the outer lining, limiting membrane separating the cell internal parts from extra cellular materials & external environment. Cytoplasm: cytoplasm is the substance that surrounds organelles and is located between the nucleus and plasma membrane 17 Human Anatomy and Physiology Organelles: these are permanent structures with characteristic morphology that are highly specialized in specific cellular activity. Inclusions: they are the secretions and storage products of cells. Extra cellular materials are also referred to as the matrix, which are substances external to the cell surface. Figure: 2.1 structure of a cell (Source: Carola, R., Harley,J.P., Noback R.C., nd (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2 Ed, pp 57) 18 Human Anatomy and Physiology 2.1.1 Plasma Membrane Plasma membrane is a thin outer membrane, which maintains the integrity of the cell. It keeps the cell and its contents separate and distinct from the surrounding. It is a double layered measuring about 4.5 nm and made of phospholipids, cholesterol, glyco-lipid, & carbohydrate (oligosaccharides). The bi-layer is self-sealing. If a needle is injected and pulled out, it automatically seals. Functions: - 1. Separate the cytoplasm inside a cell from extra cellular fluid. 2. Separate cell from one another 3. Provide an abundant surface on which chemical reaction can occur. 4. Regulate the passage of materials in to and out of cells. It also let some things in and keeps others out. The quality selective permeability Movement across-cell membrane Movements a cross membrane takes place in two ways. These are passive and active movements. Passive movement uses energy whereas active movement consumes energy in the form of ATP. 19 Human Anatomy and Physiology Passive movement: includes a. Simple diffusion, the random movements of molecules from area of high concentration to the area of low concentration. Example air in alveoli of lung b. Facilitated diffusion, larger molecules, which are not soluble in lipid need protein channel to pass through the plasma membrane. No direct energy needed. Example: - Amino acid passes through the cell membrane. c. Osmosis, a special type of diffusion referring to the passage of water through a selectively permeable membrane from an area of high water concentration to lower water concentration. d. Filtration, small molecules pass through selectively permeable membrane in response to force of pressure. Example: - filtration in the kidney in the process of urine formation. Active movements across membranes Substances move through a selectively permeable membrane from areas of low concentration on side of a membrane to an area of higher concentration on the other side. This is against concentration gradient. Therefore, it requires energy. a) Active Transport: till equilibrium substances could more by passive movement. But if equilibrium reached and still more molecules are needed, they must be pumped 20 Human Anatomy and Physiology through the membrane against concentration gradient. This process requires the use of ATP. One example of such processes is Sodium – potassium pump and calcium pump. In this process all follows similar process. These are molecules bind to carrier protein, molecule- carrier complex pass through the membrane, assisted by an enzyme & ATP and carrier protein returns to its original shape & repeat the process. b) Endocytosis, pocketing in by plasma membrane. It includes: Pinocytoss – cell drinking Receptor – mediated Endocytosis- Endocytosis with the help of receptor. Phagocytosis- cell eating. c) Exocytosis, opposite to Endocytosis, to remove out undigested particles. 2.1.2 Cytoplasm Cytoplasm is a matrix or ground substance in which various cellular components are found. It is thick semi transparent, elastic fluid containing suspended particles and a series of minute tubules and filaments that form cytoskeleton. Water constitutes 75-90% of the cytoplasm. It also contains solid components, proteins, carbohydrates, lipids and inorganic substances. The inorganic components exist as solutions 21 Human Anatomy and Physiology because they are soluble in water. The majority of organic substances however are found as colloids. Colloids are particles that remain suspended in the surrounding medium. 2.1.3 Organelles Organelles are specialized portion of the cell with a characteristic shape that assume specific role in growth, maintenance, repair and control. a) Nucleus, Oval in shape and is the largest structure in the cell. Contain the hereditary factor in the cell. Hence it controls cell activity & structure. Most cell contain single nucleus but some like matured Red Blood cell do not contain. However Muscle cell contain several nucleuses. The nucleus separated from other cell structure by double membrane called nuclear membrane. Pores over the nuclear membrane allow the nucleus to communicate with the cytoplasm. In the nucleus a jelly like fluid that fill the nucleus is karylymph (neucleoplasm), which contain the genetic material called chromosome. Nucleus also contain dark, somewhat spherical, non-membrane bound mass called nucleolus. It contains DNA, RNA and protein, which assist in the construction of ribosome. b) Ribosome, tiny granules, composed of Ribosomal RNA (rRNA). They are site of protein synthesis 22 Human Anatomy and Physiology c) Endoplasmic reticulum is a double membrane channel. It is continuous with the nuclear membrane. It involved in intracellular exchange of material with the cytoplasm. Various products are transported from one portion of the cell to another via the endoplasmic reticulum. So it is considered as intracellular transportation. It is also storage for synthesized molecules. Together with the Golgi complex it serves as synthesis & packaging center. Endoplasmic reticulum (ER) is divided in to two. These are, granular E.R. Containing granule and involving in synthesis of protein and agranular E.R. that synthesize lipid & involves in detoxification. d) Golgi Complex, near to the nucleus. It consist 4-8 membranous sacs. It process, sort, pack & deliver protein to various parts of the cell. e) Mitochondria, a small, spherical, rod shaped or filamentous structure. It generates energy. Each mitochondria posses two membrane, one is smooth (upper) membrane and the other is arranged with series of folds called cristae. The central cavity of a mitochondrion enclosed by the inner membrane is the matrix. f) Lysosomes appear as membrane enclosed spheres. They are formed from Golgi complexes & have single membrane. They contain powerful digestive (hydrolytic 23 Human Anatomy and Physiology enzyme capable of breaking down many kinds of molecules. The lysosomal enzyme believed to be synthesized in the granular endoplasmic reticulum and Golgi complex. g) The cyto-skeleton, the cytoplasm has a complex internal structure consisting of a series of exceedingly small microfilaments, microtubule & intermediate filaments together referred to as the cyto-skeleton. h) Centrosme, a dense area of cytoplasm generally spherical and located near the nucleus it contain centrioles. It also contains DNA that controls their replication. Centrosmes are made of microtubules, which seam drinking straws. They are Involved in the movement of chromosome during cell division. i) Cilia/flagella, thread like appendages, which are made of microtubules. When they are beating forms rhythmic movement. They are found in female reproductive organ and upper respiratory tube. 2.1.4 Cell inclusion Large and diverse group of chemicals, which are produced by cells, are cell inclusions. It is mainly organic and includes melanin, glycogen & Lipids. 24 Human Anatomy and Physiology 2.2 Cells out of control/cancer Normal human body cells usually divide at a controlled rate required to replace the dying ones and for growth. Cancer cells are different. They lack the controlling mechanism. Cancer occurs when cells grows and divide at abnormal rate & then spread beyond the original site. Some of the risk factors for cancer occurrence are radiation, chemicals, extreme pressure and hormonal therapy. 25 Human Anatomy and Physiology Review Questions 1) The random movement of molecules from an area of high concentration to an area of lower concentration is called: - a. Diffusion b.Exocytosis c. Facilitated diffusion d. Active transport e. Endocytosis 2) The most important structural elements of the cyto- skeleton are: - a. Microfilaments b. Vacuoles c. Ribosome d. Asters e. Microtubules 3) Mitochondria functions in the synthesis of a. DNA b. MRNA c. ATP d. rRNA e. tRNA 4) The nucleolus a. Is the site of ribosomal RNA synthesis b. Has a surrounding structure c. Contains ATP used in chromosome replication d. It is smaller in secretary cell than in non-secretary. e. Specifies the chemical structure of enzymes. 5) The Centrosme contains a. Endoplasmic reticulum b. Cilia c. Centrioles d. Flagella e. Vacuoles 26 Human Anatomy and Physiology CHAPTER THREE TISSUES & MEMBRANES Learning Objective At the end of this chapter, the students should be able to: - Describe types of tissues a) Epithelial tissue b) Connective tissue c) Nerve tissue d) Muscle tissue - Explain location and function of tissues in the body - Discuss membranes of the body Selected Key terms: The following terms are defined in the glossary Cartilage Nervous tissue Connective tissue Osseous tissue Epithelial tissue Serous membrane Glandular tissue Synovial membrane Mucus membrane Tissue Muscle tissue Vascular tissue 27 Human Anatomy and Physiology 3.1 TISSUE Cells are highly organized units. But in multicultural organisms, they do not function in isolation. They work together in-group of similar cells called tissue. Tissue is a group of similar cell and their intercellular substance that have a similar embryological origin and function together to perform a specialized activity. A science that deals with the study of a tissue is Histology. The various tissues of the body are classified in to four principal parts according to their function & structure. These are epithelial, connective, muscular, and Nervous tissue. 3.1.1 Epithelial tissue Epithelial tissues covers body surface, lines body cavity & ducts and form glands. They are subdivided in to: - Covering & lining epithelium - Glandular epithelium Covering and lining epithelium: it forms the outer covering of external body surface and outer covering of some internal organs. It lines body cavity, interior of respiratory & gastro intestinal tracts, blood vessels & ducts and make up along with the nervous tissue (the parts of sense organs for smell, 28 Human Anatomy and Physiology hearing, vision and touch). It is a tissue from which gametes (egg & sperm) develops. Covering and lining epithelium are classified based on the arrangement of layers and cell shape. According to the arrangement of layers covering and lining epithelium is grouped in to: a) Simple epithelium: it is specialized for absorption, and filtration with minimal wear & tear. It is a single layered b) Stratified epithelium, it is many layered and found in an area with high degree of wear & tear. c) Pseudo-stratified, is a single layered but seam to have many layer. Based on the cell shape covering and lining epithelium is grouped in to: a) Squamous: - flattened & scale like b) Cuboidal: - cube shaped c) Columnar: - tall & cylindrical d) Transitional: - combination of cell shape found where there is a great degree of distention or expansion, these may be cuboidal to columnar, cuboidal to polyhydral and cuboidal to Squamous 29 Human Anatomy and Physiology Therefore considering the number of layers and cell shape we can classify covering and lining epithelium in to the following groups: Simple epithelium a) Simple – Squamous epithelium, contain single layer of flat, scale like resemble tiled floor. It is highly adapted to diffusion, osmosis & filtration. Thus, it lines the air sacs of lung, in kidneys, blood vessels and lymph vessels. b) Simple – cuboidal epithelium, Flat polygon that covers the surface of ovary, lines the anterior surface of lens of the eye, retina & tubules of kidney c) Simple – columnar epithelium, Similar to simple cuboidal. It is modified in several ways depending on location & function. It lines the gastro-intestinal tract gall bladder, excretory ducts of many glands. It functions in secretions, absorption, protection & lubrication. Stratified epithelium It is more durable, protects underlying tissues form external environment and from wear & tear. a) Stratified Squamous epithelium: In this type of epithelium, the outer cells are flat. Stratified squamous epithelium is subdivided in to two based on presence of keratin. These are Non-Keratnized and Keratinized stratified squamous 30 Human Anatomy and Physiology epithelium. Non-Keratnized stratified squamous epithelium is found in wet surface that are subjected to considerable wear and tear. Example: - Mouth, tongue and vagina. In Keratinized, stratified squamous epithelium the surface cell of this type forms a tough layer of material containing keratin. Example: skin. Keratin, is a waterproof protein, resists friction and bacterial invasion. b) Stratified cuboidal epithelium, rare type of epithelium. It is found in seat glands duct, conjunctiva of eye, and cavernous urethra of the male urogenital system, pharynx & epiglottis. Its main function is secretion. c) Stratified columnar epithelium, uncommon to the body. Stratified columnar epithelium is found in milk duct of mammary gland & anus layers. It functions in protection and secretion. Transitional epithelium The distinction is that cells of the outer layer in transitional epithelium tend to be large and rounded rather than flat. The feature allows the tissue to be stretched with out breakage. It is found in Urinary bladder, part of Ureters & urethra. 31 Human Anatomy and Physiology Pseudo stratified epithelium Lines the larger excretory ducts of many glands, epididymis, parts of male urethra and auditory tubes. Its main function is protection & secretion 3.1.2 Glandular Epithelium Their main function is secretion. A gland may consist of one cell or a group of highly specialized epithelial cell. Glands can be classified into exocrine and endocrine according to where they release their secretion. Exocrine: Those glands that empties their secretion in to ducts/tubes that empty at the surface of covering. Their main products are mucous, oil, wax, perspiration and digestive enzyme. Sweat & salivary glands are exocrine glands. Endocrine: They ultimately secret their products into the blood system. The secretions of endocrine glands are always hormones. Hormones are chemicals that regulate various physiological activities. Pituitary, thyroid & adrenal glands are endocrine. Classification of exocrine glands They are classified by their structure and shape of the secretary portion. According to structural classification they are grouped into: 32 Human Anatomy and Physiology a) Unicellular gland: Single celled. The best examples are goblet cell in Respiratory, Gastrointestinal & Genitourinary system. b) Multicultural gland: Found in several different forms By looking in to the secretary portion exocrine glands are grouped into a) Tubular gland: If the secretary portion of a gland is tubular. b) Acinar gland: If the secretary portion is flask like. C) Tubulo-acinar: if it contains both tubular & flask shaped secretary portion. Further more if the duct does not branch it is referred as a simple gland and if it branch's it is compound gland. By combining the shape of the secretary portion with the degree of branching of the duct of exocrine glands are classified in to - Unicellular - Multi-cellular ƒ Simple tubular Branched tubular Coiled tubular Acinar Branched Acinar 33 Human Anatomy and Physiology - Compound Tubular Acinar Tubulo-acinar 3.1.2 Connective tissue Connective tissues of the body are classified into embryonic connective tissue and adult connective tissue. Embryonic connective tissue Embrayonic connective tissue contains mesenchyme & mucous connective tissue. Mesenchyme is the tissue from which all other connective tissue eventually arises. It is located beneath the skin and along the developing bone of the embryo. Mucous (Wharton’s Jelly) connective tissue is found primarily in the fetus and located in the umbilical cord of the fetus where it supports the cord. Adult connective tissue It is differentiated from mesenchyme and does not change after birth. Adult connective tissue composes connective tissue proper, cartilage, osseous (bone) & vascular (blood) tissue 34 Human Anatomy and Physiology a) Connective tissue proper, connective tissue proper has a more or less fluid intercellular martial and fibroblast. The various forms of connective tissue proper are: Loose (areolar) connectives tissue, which are widely distributed and consists collagenic, elastic & reticular fibers and several cells embedded in semi fluid intercellular substances. It supports tissues, organ blood vessels & nerves. It also forms subcutaneous layer/superficial fascia/hypodermis. Adipose tissue: It is the subcutaneous layer below the skin, specialized for fat storage. Found where there is loose connective tissue. It is common around the kidney, at the base and on the surface of the heart, in the marrow of long bone, as a padding around joints and behind the eye ball. It is poor conductor of heat, so it decrease heat loss from the body Dense (Collagenous) connective tissue: Fibers are closely packed than in loose connective tissue. Exists in areas where tensions are exerted in various directions. In areas where fibers are interwoven with out regular orientation the forces exerted are in many directions. This occurs in most fascia like deeper region of dermis, periosteum of bone and membrane capsules. In other areas dense connective tissue adapted tension in one direction and fibers have parallel arrangement. Examples are tendons 35 Human Anatomy and Physiology and ligaments. Dense connective tissues provide support & protection and connect muscle to bone. Elastic connective tissue: Posses freely branching elastic fibers. They stretch and snap back in to original shape. They are components of wall of arteries, trachea, bronchial tubes & lungs. It also forms vocal cord. Elastic connective tissue allows stretching, and provides support & suspension. Reticular connective tissue: Lattice of fine, interwoven threads that branch freely, forming connecting and supporting framework. It helps to form a delicate supporting storma for many organs including liver, spleen and lymph nodes. It also helps to bind together the fibers (cells) of smooth muscle tissue. b) Cartilage Unlike other connective tissue, cartilages have no blood vessels and nerves. It consists of a dense network of collagenous fibers and elastic fibers firmly embedded in chondriotin sulfate. The strength is because of collagenous fibers. The cells of a matured cartilage are called chondrocyte. The surface of a cartilage is surrounded by irregularly arranged dense connective tissue called perichondrium. Cartilages are classified in to hyaline, fibro & elastic cartilage. 36 Human Anatomy and Physiology Hyaline cartilage is called gristle, most abundant, blue white in color & able to bear weight. Found at joints over long bones as articlar cartilage and forms costal cartilage (at ventral end of ribs). It also forms nose, larynx, trachea, bronchi and bronchial tubes. It forms embryonic skeleton, reinforce respiration, aids in free movement of joints and assists rib cage to move during breathing. Fibro cartilage: they are found at the symphysis pubis, in the inter-vertebral discs and knee. It provides support and protection. Elastic cartilage: in elastic cartilage the chondrocyte are located in thread like network of elastic fibers. Elastic cartilage provides strength and elasticity and maintains the shape of certain organs like epiglottis, larynx, external part of the ear and Eustachian tube. c) Osseous tissue (Bone) The matured bone cell osteocytes, embedded in the intercellular substance consisting mineral salts (calcium phosphate and calcium carbonate) with collagenous fibers. The osseous tissue together with cartilage and joints it comprises the skeletal system. 37 Human Anatomy and Physiology d) Vascular tissue (Blood tissue) It is a liquid connective tissue. It contains intercellular substance plasma. Plasma is a straw colored liquid, consists water and dissolved material. The formed elements of the blood are erythrocytes, leukocytes and thrombocytes. The fibrous characteristics of a blood revealed when clotted. 3.1.3 Muscle tissue Muscle tissue consists of highly specialized cells, which provides motion, maintenance of posture and heat production. Classification of muscles is made by structure and function. Muscle tissues are grouped in to skeletal, cardiac and smooth muscle tissue. - Skeletal muscle tissue are attached to bones, it is voluntary, cylindrical, multinucleated & striated - Cardiac muscle tissue: It forms the wall of the heart; it is involuntary, uni-nucleated and striated. - Smooth muscle tissue: located in the wall of hallow internal structure like Blood vessels, stomach, intestine, and urinary bladder. It is involuntary and non-striated. 38 Human Anatomy and Physiology 3.1.4 Nervous tissue Nervous tissue contains two principal cell types. These are the neurons and the neuroglia. Neurons are nerve cells, sensitive to various stimuli. It converts stimuli to nerve impulse. Neurons are the structural and functional unit of the nervous system. It contains 3 basic portions. These are cell body, axons and dendrites. Neuroglias are cells that protect, nourish and support neurons. Clinically they are important because they are potential to replicate and produce cancerous growths. 3.2 Membranes Membranes are thin pliable layers of epithelial and/or connective tissue. They line body cavities, cover surfaces, connect, or separate regions, structures and organs of the body. The three kinds of membranes are mucous, serous and synovial. Mucous membranes (mucosa) lines body cavity that opens directly to the exterior. It is an epithelial layer. Mucous membranes line the entire gastro intestine, respiratory excretory and reproductive tracts and constitute a lining layer of epithelium. The connective tissue layer of mucous membrane is lamina propra. To 39 Human Anatomy and Physiology prevent dry out and to trap particles mucous membranes secret mucous. Serous membrane / serosa: contains loose connective tissue covered by a layer of mesothelium. It lines body cavity that does not open directly to the exterior. Covers the organs that lie with in the cavity. Serosa is composed of parietal layer (pertaining to be outer) and visceral layer (pertaining to be near to the organ). Pleura and pericardium are serous membrane that line thoracic and heart cavity respectively. The epithelial layer of a serious membrane secret a lubricating fluid called serious fluid. The fluid allows organs to glide one another easily. Synovial membrane: Unlike to other membranes this membrane does not contain epithelium. Therefore, it is not epithelial membrane. It lines the cavities of the freely movable joints. Like serious membrane it lines structures that do not open to the exterior. Synovial membranes secret synovial fluid that lubricate articular cartilage at the ends of bones as they move at joints. 40 Human Anatomy and Physiology Review Questions 1. Unicellular glands composed of columnar cells that secrete mucous are known as:- a) Cilia b) Microvilli c) Goblet cell d) Endocrine glands e) Basal cell 2. A group of similar cell that has a similar embryological origin and operates together to perform a specialized activity is called:- a) Organ b) Tissue c) System d) Organ system e) Organism 3. Mucous membranes a) Lines cavities of the body that are not open to the outside b) Secret thin watery serous fluid c) Cover the outside of such organs as the kidney and stomach d) Are found lining the respiratory & urinary passages e) Are described by none of the above. 41 Human Anatomy and Physiology 4. Which of the following is involuntary and striated? a) Skeletal muscle tissue b) Cardiac muscle tissue c) Smooth muscle tissue d) Visceral muscle tissue e) Neural tissue 5. Which tissue is characterized by the presence of cell bodies, dendrites and axons? a) Muscle b) Vascular c) Nervous d) Epithelial e) Osseous 42 Human Anatomy and Physiology CHAPTER FOUR THE INTEGUMENTARY SYSTEM Chapter objectives: At the end of this chapter, the students should be able to - Describe skin of the human body - Discuss glands of the skin - Explain the structure and function of hair - Discuss about nails Selected Key terms: The following terms are defined in the glossary: Dermis Epidermis Eponychiem Hypodermis Hyponychium Lunula Sebaceous glands Sudoriferous glands 43 Human Anatomy and Physiology The Integumentary system consist the skin and its derivatives. These include hair, nails, and several types of glands. The system functions in protection, in the regulation of body temperature, in the excretion of waste materials, in the synthesis of vitamin D3 with the help of sunrays, and in the reception of various stimuli perceived as pain, pressure and temperature. 4.1 Skin Skin is the largest organ in the body occupying almost 2m2 of surface area thickens of 2mm. Skin has 3 main parts. These are the epidermis, dermis and hypodermis. Epidermis is the outer layer of the skin that is made of stratified squamous epithelium. It has no blood supply. Epidermis contains 4-5 strata. These are stratum cornium, lucidium, granulosum, spinosum and basale, Stratum cornium is the outer, dead, flat, Keratinized and thicker layer. Stratum lucidium is next to stratum cornium. It consists of flat, translucent layers of cells. This stratum found in thick skin only. Stratum granulosum lies just below stratum lucidium. The cells in this layer are in the process of keratinization. 44 Human Anatomy and Physiology Stratum spinosum: next down to stratum granulosum. The cells in this stratum have a poly-hydral shape and they are in the process of protein synthesis. Stratum basale rests on the basement membrane, and it is the last layer of epidermis next to stratum spinosum. Stratum basale together with stratum spinosum constitute stratum germinativum. Dermis / true skin/ a strong, flexible, connective tissue mesh work of collagen, reticular and elastic fibers. Most part of the skin is composed of dermis. Dermis contains papillary and reticular layers. Papillary layer is next to stratum basale of the epidermis. It contains loose connective tissue with in the bundles of collagenous fibers. It also contains loose capillaries that nourish the epidermis. In some areas papillary layer have special nerve endings that serve as touch receptors (meissner’s corpuscles). Indentations of papillary layer in the palms and soles reflected over the epidermis to create ridges. Reticular layer: next to papillary layer. It is made of dense connective tissue with course of collagenous fiber bundles that crisscross to form a storma of elastic network. In the reticular layer many blood and lymphatic vessels, nerves, fat cell, sebaceous (oil) glands and hair roots are embedded. 45 Human Anatomy and Physiology Receptors of deep pressure (pacinian corpuscles) are distributed through out the dermis. Hypoderms: it is found beneath the dermis. It is a subcutaneous layer (under the skin). Hypodermis is composed of loose, fibrous connective tissue, which is richly supplied with lymphatic and blood vessels and nerves. Hypodermis is much thicker than dermis. With in it coils of ducts of sudoriferous (sweat) glands, and the base of hair follicles. Figure: 4.1 The skin (source: Carola, R., Harley,J.P., Noback R.C., (1992), nd Human anatomy and physiology, Mc Graw hill inc, New York, 2 ed, pp 124) 46 Human Anatomy and Physiology 4.1.1 Functions of Skin 1. Protection: against harmful microorganisms, foreign material and it prevents excessive loss of body fluid. 2. Temperature regulation: with the sweat, heat leaves the body 3. Excretion: Small amount of waste products from the body such as urea 4. Synthesis: By the action of UV. Vitamin D is synthesized in the skin. Vitamin D is necessary for absorption calcium from intestine. 5. Sensory reception: it contains sensory receptors of heat, cold, touch, pressure, and pain. 4.1.2 Color of the skin Skin’s color is determined by 3 factors 1. The presence of melanin a dark pigment produced by specialized cell called melanocyte 2. The accumulation of yellow pigment carotene. 3. The color of blood reflected through the epidermis * The main function of melanin is to screen out excessive ultraviolet rays. * All races have some melanin in their skins although the darker races have slightly more melanocyte. The person 47 Human Anatomy and Physiology who is genetically unable to produce any melanin is an albino. 4.2 Glands of the Skin Glands of the skin are the sudoriferous and sebaceous glands. 4.2.1. Sudoriferous /sweat/ glands Types: Eccrine and Apocrine glands Eccrine glands are small, simple coiled tubular glands distributed over nearly the entire body, and they are absent over nail beds, margins of lips of vulva, tips of penis. Eccrine glands are numerous over the palms and soles. Their secretary portion is embedded in the hypodermis. The sweat they secret is colorless, aqueous fluid containing neutral fats, albumin, urea, lactic acid and sodium chloride. Its excretion helps body temperature to be regulated. Apocrine glands are odiferous, found at the armpits, in the dark region around nipples, the outer lips of the vulva, and the anal and genital regions. They are larger and deeply situate than eccrine sweet glands. An apocrine sweet gland becomes active at puberty. They respond to stress including sexual activity. The female breasts are apocrine glands that have 48 Human Anatomy and Physiology become adapted to secret and release milk instead of sweat. The ceruminous glands in the outer ear canal are also apocrine skin glands. 4.2.2 Sebaceous (Oil) glands Sebaceous glands are simple branched alveolar glands found in the dermis. Their main functions are lubrication and protection. They are connected to hair follicles and secret oily secretion called sebum. It is a semi fluid substance composed of entirely lipids. It functions as a permeability barrier, an emollient (skin softening) and a protective a gent against bacteria and fungi. This type of gland found all over the body except in the palms and soles. Acne vulgaris is a condition when there is over secretion of sebum, which may enlarge the gland and plug the pore. 4.3 Hair Hair is composed of Keratinized threads of cells, which develops from the epidermis. Because it arises from the skin, it is considered an appendage of the skin. It covers the entire body except the palms, soles, lips, tip of penis, inner lips of vulva and nipples. 49 Human Anatomy and Physiology 4.3.1 Function - Insulation against cold in scalp - Against glare in eye brows - Screen against foreign particles (eye lashes) - In the nostrils trap dust particles in the inhaled air - Protect openings from foreign particles. 4.3.2 Structure of Hair Hair has two parts, the shaft the part above skin and the root embedded in the skin. Hair consist epithelial cell arranged in three layers from the inside out medulla, cortex and cuticle. Figure: 4.2 Structure the Hair (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, nd 2 ed, pp132) 50 Human Anatomy and Physiology y The lower portion of the root, located in the hypodermis enlarges to form the bulbs. The bulb is composed of the matrix of epithelial cells. The bulb pushes in ward along its bottom to form a papilla of blood rich connective tissue. Part of the hair follicle is attached with the bundle of smooth muscle about halfway down the follicle. These are arrecter pili muscles. When it contracts in pulls the follicles and its hair to an erect position producing goose bump. Hair grows and when it finishes its growth sheds. The growth rate of hair depends on its position. The fastest growth rate occurs over 51 Human Anatomy and Physiology the scalp of women aged 16 to 24 years. Scalp hair grows 0.4 m.m per day (an average scalp contain 125.000 hairs). Hair sheds when it growth is complete. Just before a hair is to be shed, the matrix cell gradually become inactive and eventually dies. 4.4 Nail Nails, like hair are modifications of the epidermis. They are made of hard keratin. Nails are composed of flat, cornified plates on the dorsal surface of the distal segment of the fingers and toe. The proximal part of nail is lunula, which is white in its color because of the capillaries underneath are covered by thick epithelium. Nail has body and root. The body is the exposed part and the root is hidden under the skin. The nail ends with a free edge that overhangs the tip of the fingers. Epithelial layer covering underneath of the fore-hang nail is hyponychyem. The nail rests on an epithelial layer of skin called nail bed. The thicker layer of skin beneath the nail root is the matrix, where new cells are generated. Nail grows 0.5 m.m a week. Thin layers of epidermis called eponychium originally cover the growing nail. Our nail protects our fingers and toes. It also allows picking up and grasping objects as well we use them to scratch. 52 Human Anatomy and Physiology Figure: 4.3 Finger nail structure (Source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2nd ed, pp 134) 53 Human Anatomy and Physiology Review Questions 1. Which of the following skin layers undergoes cellular regeneration? a) Stratum basale b) Stratum spinosum c) Stratum granulosum d) a and b only e) a, b and c 2. Which of the following is /are found in the reticular layer of the skin? a) Blood and lymph vessels b) Nerves c) Sensory nerve endings d) Sebaceous glands e) All of the above 3. Skin gets its color from a) Carotene b) Underlying blood vessels c) Melanin d) a and b only e) a, b and c 54 Human Anatomy and Physiology 4. Sudoriferous glands secret their secretion in response to: a) Physiological process b) Heat c) Stress d) Sexual experience e) In all of the above condition 5. Hair covers all of the following parts of the body except: - a) Sole b) Face c) Neck d) Trunk. e) Outer vulva 55 Human Anatomy and Physiology CHAPTER FIVE THE SKELETAL SYSTEM Learning Objective At the end of this chapter, the students should be able to: Discuss bone tissue. Explain the general feature and surface markings of bones. Discuss skeleton and its function: - Axial skeleton - Appendicular skeleton. Explain joints, types of joints and their movements Selected Key terms The following terms are defined in the glossary: Appendicular skeleton Myeloid tissue Articulation Orbits Axial skeleton Ossicles Bone cell Ossification Cranium Perichondrium 56 Human Anatomy and Physiology Diaphysis Periosteum Endosteum Skull Epiphyseal plate Surface marking Epiphysis Sutures Fontanel Tendons Intervertibral disc Thorax Metaphysis Vertebrae The word skeleton comes from the Greek word skeleton meaning “dried up”. It is strong yet light adapted for its function of body protection and motion. The skeletal system includes bones, joints, cartilages and ligaments. The joint give the body flexibility and allow movements to occur. But from structural point of view, the human skeletal system consists of two main types of supportive connective tissue, bone and cartilage. Functions of the skeletal system: 1. Support: it forms the internal framework that supports and anchors all soft organs. 2. Protection: bones protect soft body organs. 3. Movement: skeletal muscles attached to the skeletal system use the bone to levers to move the body and its part. 57 Human Anatomy and Physiology 4. Storage: fat is stored in the internal cavities of bones. Bone it self-serves as a storehouse of minerals. The most important being calcium and phosphors. 5. Blood cell formation: it occurs with in the marrow cavities of certain bones. 5.1 Bone Bone (osseous) is specialized connective tissue that has the strength of cast iron and lightness of pinewood. Living bone is not dry, brittle or dead. It is a moist changing, productive tissue that is continually resorbed, reformed and remodeled. 5.1.1 Types of bone Long bone, are called long as its length is greater than its width. The most obvious long bones are in the arm and leg. They act as levers that pulled by contraction of muscles. Short bones are about equal in length, width and thickness, which are shaped with regular orientation. They occur in the wrist and ankle. Flat bones are thin or curved more often they are flat. This includes ribs, scapulae, sternum and bone of cranium. Irregular bones, they do not fit neatly into any other category. Examples are the vertebral, facial, and hipbone. 58 Human Anatomy and Physiology Sesamoid bones are small bones embedded with in certain tendons, the fibrous cord that connects muscle to bones. Typical sesamoid bones are patella and pisiform carpal bone, which are in the tendon of quadriceps femuris and flexor carp ulnaris muscle respectively. Accessory bones are most commonly found in the feet. They usually occur in the developing bone and do not fuse completely. They look like extra bones or broken on X-ray. Sutural (wormian) bones are examples of accessory bones. Figure: 5.1 Types of bones (Source: Elaine n. MARIEB, (2000), Essentials of human anatomy and physiology, Addison welsey longman inc., San th Francisco, 6 Ed) 59 Human Anatomy and Physiology 5.1.2. Gross anatomy of a typical long bone You can take Tibia (in the leg) one of the longest bones in the body. In adults it have: Diaphis, the tubular shaft, hallow cylindrical with walls of compact bone tissue. The center of the cylinder is the medullary cavity, which is filled with marrow. Epiphysis is roughly spherical end of the bone. It is wider than the shaft. Flat and irregular bones of the trunk and limbs have many epiphysis and the Figure: 5.2 Typical long bone (Source: Carola, R., Harley,J.P., long bones of the finger and toe Noback R.C., (1992), Human anatomy and physiology, Mc have only one epiphysis. nd Graw hill inc, New York, 2 ed, pp 145) Metaphysis is the part separating diaphysis from epiphysis. It is made up of epiphyseal plate and adjacent bony trabeculae of cancellous bone tissue. 60 Human Anatomy and Physiology Epiphyseal plate is a thick plate of hyaline cartilage, which provides the framework of synthesis of the cancellous bone tissue within metaphysis. The medullary cavity running through the length of the diaphysis contains Yellow marrow. The porous latticework of the spongy epiphyses is filled with red bone marrow. The red marrow also known as myeloid tissue Endosteum is the lining the medullary cavity of compact bone tissue and covering the trabeculae of spongy bone tissue. Periosteum: it is covering the outer surface of the bone. It is absent at joints and replaced by articular cartilage. 5.1.3 Bone (Osseous) Tissue Bone tissue is composed of cells embedded in a matrix of ground substances and fibers. It is more rigid than other tissues because it contains inorganic salts mainly calcium phosphate & calcium carbonate. A network of collagenous fibers in the matrix gives bone tissue its strength and flexibility. Most bones have an outer sheet of compact bone tissue enclosing an interior spongy bone tissue. 61 Human Anatomy and Physiology Compact bone tissue forms the outer sheet of a bone. It is very hard and dense. It appears to naked eye to be solid but not. Compact bone tissue contains cylinders of calcified bone known as osteons (Haversion system). Osteons are made up of concentric layers called lamellae, which are arranged seemingly in wider and wider drinking straws. In the center of the osteons are central canals (haversion canal) , which are longitudinal canals that contains blood vessels, nerves and lymphatic vessels. Central canals, usually have branches called perforating canals /valkmann’s canal that run at right angle to central canal extending the system of nerves and vessels out ward to periosteum and to endosteum. Lacunae (Little spaces) that houses osteocytes (bone cells) are contained in lamella. Radiating from each lacuna are tiny canaliculi containing the slender extensions of the osteocytes where nutrients and wastes can pass to and from central canal. Spongy (cancellous) Bone tissue Is in the form of an open interlaced pattern that withstands maximum stress and supports in shifting stress. Trabeculae are tiny spikes of bone tissue surrounded by bone matrix that has calcified. 62 Human Anatomy and Physiology Figure: 5.3 Compact bone tissues (Source: Elaine n. MARIEB, (2000), Essentials of human anatomy and physiology, Addison th welsey longman inc., San Francisco, 6 Ed) Bone Cells Bone contain five types of cells a) Osteogenic (osteoprogenitor) cells: these are small spindle shaped cell. They found mostly in the deepest layer of periosteum and endosteum. They have high mitotic potential and can be transformed into bone forming cells (osteoblasts). b) Osteoblasts are found in the growing portion of bone including periosteum. They are able to synthesize and 63 Human Anatomy and Physiology secrete un-mineralized ground substance, act as pump cell to move calcium and phosphate in and out of bone tissue. c) Osteocytes are the main cell of fully developed bones. They have a cell body that occupies a lacuna. Osteocytes are derived from osteoblasts. They together with osteoclasts play an important role of homeostasis by helping to release calcium. d) Osteoclasts are multinuclear giant cell, which are found where bone is resorbed during its normal growth. Osteoclasts are derived from white blood cells called monocytes. e) Bone - lining cells are found on the surface of most bones in the adult skeleton. They are believed to be derived from osteoblast that ceases their physiological activity. 5.1.5 Developmental Anatomy and Growth of Bones Bones develop through a process known as Ossification. Bone in embryo develops in two ways: Intra-membranous ossification, If bone develops directly from mesenchymal tissue. Examples are vault of the skull, flat bones and part of the clavicle. In this type of ossification development continues rapidly from the center. Endochondrial Ossification, When bone tissue develops by replacing hyaline cartilage. The 64 Human Anatomy and Physiology cartilage it self do not converted into bone but the cartilage is replaced by bone through the process. Endochondrial ossification produces long bones and all other bones not formed by intra-membranous ossification. Function of bone Supportive and protection of internal organs. The store house and main supply of reserve calcium and phosphate. The manufacture of red and white blood cell. Table 5.1 Comparison between bone and cartilage (Source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2nd ed, pp 153) Feature Bone Cartilage Components Bone cells Ground Cartilage cell chondrocyte substances mineral Collagenous fiber Ground component substances Locations of cell In lacunae In lacunae Outer covering Periosteum Perichondrium Derivation Mesenchyme Mesenchyme Blood vessels Contain B/V Has no B/v Strength Stronger than cartilage Not strong as bone Nutrients By capillaries to cell by From tissue fluid by diffusion Through diffusion canaliculi 65 Human Anatomy and Physiology 5.2 The Skeleton General futures and surface markings Looking to the bone reveals the surface is not smooth but scarred with bumps, holes and ridges. These are surface markings where muscles, tendons and ligaments attached, blood & lymph vessels and nerves pass. Depression and openings Fissure narrow, cleft like opening between adjacent parts of bone. Example: Supra of orbital fissure. Foramen, a bigger, round opening. Example: Foramen magnum. Meatus: a relatively narrow tubular canal. Example: External auditory meatus Groves and sulcus: are deep furrow on the surface of a bone or other structure. Example: Inter-vertebral and radial groves of humers. Fossa: shallow depressed area. Example: Mandibular fossa. Processes that form joints Condyle / knuckle like process/ concave or convex. Example Medial condyle of femur Head, expanded, rounded surface at proximal end of a bone often joined to shaft by a narrowed neck. Example: Head of femur Facet: small, flat surface. Example: Articular facet of ribs. 66 Human Anatomy and Physiology Process to which tendons, ligaments and other Connective tissue attach Tubercle: it is a knob like process. Example: Greater tubercle of humerus. Tuberosity: it is large, round roughened process. Example: ischeal tuberosity. Trochanter: it is a large, blunt projection found only on femur Crest is a prominent ridge. Example: Iliac crest. Line: it is a less prominent ridge than a crest. Spinous process (spine) is a sharp, slender process. Example Ischeal spin Epicondyle is a prominence above condyle. Example medial Epicondyle of Femur 5.2.2 Division of the skeletal system The Adult human skeletons have 206 named bones that are grouped in to two principal parts. These are the axial and appendicular skeleton. The Axial skeleton consist bones that lie around the axis. And the appendicular skeleton consist bones of the body out of the axial group. These are appendages. Upper & lower extremities and bones of girdles are grouped under appendicular skeleton. 67 Human Anatomy and Physiology Figure: 5.4 Axial and Appendicular skeleton (Source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and nd physiology, Mc Graw hill inc, New York, 2 ed, pp 166) 68 Human Anatomy and Physiology Table 5.2 Divisions of The Adult Skeleton (206 Bones) AXIAL SKELETON APPENDICULAR SKELETON Skull (29 bones)* Upper extremities (64 bones) Cranium 8 Pectoral (shoulder) girdle 4 Parietal (2) Clavicle (2) Temporal (2) Scapula (2) # Frontal (1) Arm 2 Ethmoid (1) Humerus (2) 4 Sphenoid (1) Forearm Occipital (1) Ulna (2) Face 14 Radius (2) Maxillary (2) Wrist 16 Zygomatic (molar) (2) Carpals (16) Lacrimal (2) Hand and fingers 38 Nasal (2) Metacarpals (10) Inferior nasal conchii (2) Phalanges (28) Palatine (2) Lower extremities (62 bones) Mandible (1) Pelvic girdle 2 Vomer (1) (Fused ileum, ischium, pubis) Ossicles of ear 6 Thigh 4 Malleus (hammer) (2) Femur (2) Incus (anvil) (2) Patella (2) Stapes (stirrup) (2) Leg 4 Hyoid 1 Tibia (2) Vertebral column (26 bones) Fibula (2) Cervical vertebrae 7 Ankle 14 Thoracic vertebrae 12 Tarsals (14) Lumbar vertebrae 5 Foot and toes 38 Sacrum (5 fused bones) 1 Metatarsals (10) Coccyx (3- 5 fused bones) 1 Phalanges (28) Thorax (25bones) Ribs 24 Sternum 1 Total axial bones 80 Total Appendicular bones 126 69 Human Anatomy and Physiology * The number of skull bones is sometimes listed as 22, when the Ossicles of the ears (6 bones) and the single hyoid bone is counted separately. Technically, the hyoid bone is not part of the skull. +The thoracic vertebrae are sometimes included in this category. # Technically, the term arm refers to the upper extremity between the shoulder and elbow; the forearm is between the elbow and wrist. The upper part of the lower extremity, between the pelvis and knee, is the thigh; the leg is between the knees an ankle. 5.2.3 The Axial skeleton 5.2.3.1 The skull It Contain 22 bones. The skull rests on the superior of vertebral column. It is composed of cranial and facial bones. 70 Human Anatomy and Physiology Table 5.3 Description and function of Cranial Bones (Source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2nd ed, pp 170) Bone Description and function Ethmoid (1) Base of cranium, anterior to body of sphenoid. Made up of horizontal, cribriform plate, median perpendicular plate, paired lateral masses; contains ethmoidal sinuses, crista galli, superior and middle conchae. Forms roof of nasal cavity and septum, part of cranium floor; site of attachment for membranes covering brain. Frontal (1) Anterior and superior parts of cranium, forehead, brow areas. Shaped like large scoop; frontal squama forms forehead; orbital plate forms roof of orbit; supraorbital ridge forms brow ridge; contains frontal sinuses, supraorbital foramen. Protects front of brain; contains passageway for nerves, blood vessels. Occipital (1) Posterior part of cranium, including base. Slightly curved plate, With turned- up edges; made up of squamous, base, and two lateral parts; contains foramen magnum, occipital condyles, hypo-glossal canals, atlanto-occipital joint, external occipital crest and protuberance. Protects posterior part of brain; forms foramina for spinal cord and nerves; site of attachment for muscles, ligaments. Parietal (2) Superior sides and roof of cranium, between frontal and occipital bones. Broad, slightly convex plates; smooth exteriors and internal depressions. Protect top, sides of brain, passageway for blood vessels. Sphenoid (1) Base of cranium, anterior to occipital and temporal bones. Wedge-shaped; made up of body, greater and lesser lateral wings, pterygoid processes; contains sphenoidal sinuses, sella turcica, optic foramen, superior orbital fissure, foramen 71 Human Anatomy and Physiology ovale, foramen rotundum, foramen spinosum Forms anterior part of base of cranium; houses pituitary gland; contains foramina for cranial nerves, meningeal artery to brain. Temporal (2) Sides and base of cranium at temples. Made up of squamous, petrous, tympanic, mastoid areas; contain zygomatic process, mandibular fossa, ear Ossicles, mastoid sinuses. Form temples, part of cheekbones; articulate with lower jaw; protect ear ossicles; site of attachments for neck muscles. Figure: 5.5 Lateral view of cranial skull (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New nd York, 2 ed, pp 170) 72 Human Anatomy and Physiology Sutures Meaning to stitch, are immovable joint found between skull bones. There are four main sutures in the skull. a) Coronal suture: between the frontal & the two-parital bone. b) Sagital suture: between the two parietal bones. c) Lambdoidal suture: between parietal & occiputal bone. d) Squamosal suture: between parietal bone and temporal bone. Fontanels The skeleton of a newly formed embryo consist cartilage or fibrous membrane structures, which gradually replaced by bone the process is called ossification. At birth membrane filled spaces on the skull are called fontanel. They are found between cranial bones. Function They enable skull of the fetus to compress as it pass through the birth canal Permit rapid growth of brain during infancy Serves as a landmark (anterior fontanel) for withdrawal of blood from the superior sagital sinus Aid in determination of fetal position prior to birth. In the skull of the fetus there are 6 prominent fontanels: a) The Anterior (frontal) fontanel, between angle of two parietal bones & segment of the frontal bone. It is diamond 73 Human Anatomy and Physiology shaped and is the largest fontanel. It closes 18 to 24 months after birth. b) The posterior (occiputal) fontanel, between parietal & occiputal bone. It is also diamond shaped but smaller than the anterior fontanel. It closes 2 months after birth. c) The Antrolatral (sphenoidal) fontanel, they are pair, one in each side. Found at the junction of frontal, parietal, temporal & sphenoidal bone. They are small & irregular in shape and closes at 3rd month after birth. d) The postrolateral (mastoid) fontanel, Paired one in each side. Found at the junction of parietal, occiputal and temporal bones. They are irregular in shape and begin to close at 1 or 2 months after birth and completed by 12 months. 74 Human Anatomy and Physiology Figure: 5.6 Sutures and Fontanels (Source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, nd 2 ed, pp 172) 75 Human Anatomy and Physiology Table 5.4: Description and function of Facial bones (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2nd ed, pp 171) Bone Descriptions and function Inferior nasal Lateral walls of nasal cavities, below superior and middle Conchii (2) conchae of Ethmoid bone. Thin, cancellous, shaped like curved leaves. Lacrimal (2) Medial wall of orbit, behind frontal process of maxilla. Small, thin, rectangular; contains depression for lacrimal sacs, nasolacrimal tear duct. Mandible (1) Lower jaw, extending from chin to mandibular fossa of temporal bone. Largest, strongest facial bone; horseshoe-shaped horizontal bony with two perpendicular rami; contains tooth sockets, coronoid, condylar, alveolar processes, mental foramina. forms lower jaw, part of temporomandibular joint; site of attachment for muscles. Maxillae (2) Upper jaw and anterior part of hard palate. Made up of zygomatic, frontal, palatine, alveolar processes; contain infraorbital foramina, maxillary sinuses, tooth sockets. Form upper jaw, front of hard palate, part of eye sockets. 76 Human Anatomy and Physiology Nasal (2) Upper bridge of nose between frontal processes of maxillae. Small, oblong; attached to a nasal cartilage. Form supports for bridge of upper nose. Palatine (2) Posterior part of hard palate, floor of nasal cavity and orbit; posterior to maxillae. L-shaped, with horizontal and vertical plates; contain greater and lesser palatine foramina. Horizontal plate forms posterior part of hard palate; vertical plate forms part of wall of nasal cavity, floor of orbit. Vomer (1) Posterior and inferior part of nasal septum. Thin, shaped like plowshare. Forms posterior and inferior nasal septum dividing nasal cavities. Zygomatic (2) Cheekbones below and lateral to orbit. Curved lateral part of (molar) cheekbones; made up of temporal process, zygomatic arch; contain zygomatico-facial and zygomatico-temporal foramina. form cheekbones, outer part of eye sockets. Hyoid(1) Below root of tongue, above larynx. U-shaped, suspended from styloid process of temporal bone; site of attachment for some muscles used in speaking, swallowing. Ossicles of ear Inside cavity of petrous portion of temporal bone. (6) Tiny bones Incus(2) shaped like anvil, hammer, stirrup, articulating with one another malleus (2) and attached to tympanic membrane. Convey sound vibrations stapes (2) from eardrum to oval window (see Chapter 16). 77 Human Anatomy and Physiology Figure: 5.7 Lateral separated view of facial skull, ear ossicles and hyoid bone (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human nd anatomy and physiology, Mc Graw hill inc, New York, 2 ed, pp 171) Orbits A pyramid shaped space that contains the eyeball & associate structures. It is formed by bones of the skull. Orbit has four walls and apex: 78 Human Anatomy and Physiology The roof of the orbit consists of parts of the frontal & sphenoid bone. The lateral wall is formed by portions of zygomatic and sphenoid bone. The floor of the orbit is formed by parts of the maxilla, zygomatic and palatine bone. The medial wall is formed by portion of the maxilla, lacrimal, ethimoid & sphenoid bone. In the orbit there are openings that pass structures. Some of the principal openings and And the structures passing through are: Optic foramen (canal) passes optic nerve Superior orbital fissure passes supra orbit nerve and artery. Inferior orbital fissure passes maxillary branch of trigeminal and zygomatic nerve and infra orbital vessel. Supra orbital foramen (notch) passes occulomotor, trochlear, ophthalmic branch of trigeminal and abducent nerves. Canal for naso lacrimal duct passes naso lacrimal duct. 79 Human Anatomy and Physiology Figure: 5.8 Skull anterior views, and the orbital cavity (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw nd hill inc, New York, 2 ed, pp 173) The vertebral column The vertebral column together with the sternum & ribs constitutes the skeleton of the trunk of the body. It composes 2/5th of the height of the body and has average length in male of 71 c.m. and in female 61 c.m. The adult vertebral column contains 26 vertebras. Prior to fusion of sacral & coccygeal vertebrae the total number is 33. It is a strong and flexible to either direction & rotated on it self. Encloses & protect spinal cord, supports the head and serves as a point of attachment for the ribs & muscles of the back. 80 Human Anatomy and Physiology Inter vertebral discs Between adjacent vertebrae from 1st to sacrum there are inter vertebral discs. They are fibro-cartilaginous. Each disc is composed of the outer fibrous ring consisting fibro-cartilage called annulus fibrosis and the inner soft, pulpy highly elastic structure called the nucleus pulpous. The disc permits various movement of the vertebral column, absorb shock and form a strong joint. Figure: 5.9 Intervertibral disc, compressed and ruptured disc (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and nd physiology, Mc Graw hill inc, New York, 2 ed, pp 196) Normal curves The vertebral column when viewed from side is not a straight line rather have bandings. These are normal curves of the vertebral column. There are 4 normal curves formed by vertebras, two are concave and the other two are convex. The presences of the curve have several functions; these are absorption of shock, maintenance of balance, protection of 81 Human Anatomy and Physiology column from fracture and increasing the strength of the column. In the age of the fetus there is only a single anterior concave curve, but approximately the third post natal month, when the child begin to hold head erect, the cervical curve develops. Later when the child sits up, stands and walks the lumbar curve develops. The cervical & lumbar curves are an anteriorly convex and because they are modification of the fetal position they are called secondary curves. The thoracic and sacral curves are anteriorly concave, since they retain the anterior concavity of the fetal curve they are referred primary curves. Figure: 5.10. The vertebral column and vertebral curves (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and nd physiology, Mc Graw hill inc, New York, 2 ed, pp 186) 82 Human Anatomy and Physiology Typical vertebra Although there are variations in size and shape, the vertebras of the different region have basically similar structure. It consist the body, vertebral arch and seven processes. The body (Centrum), thick, disc shaped, anterior part. It has superior and inferior roughened area for attachment with intervertebral discs. The vertebral (neural) arch extends posterior from the body of the vertebrae. With the body it surrounds the spinal cord. It is formed by two short, thick process called pedicles. It projects posteriorly to meet at laminae. The laminae are flat parts that join to form the posterior portion of the vertebral arch. The space that lies between the vertebral arch and body contains the spinal cord called vertebral foramina. The vertebral foramina of all vertebras together form the vertebral (spinal) canal. The pedicles are notched superiorly & inferiorly to form an opening between vertebrae on each side of the column called Intervertibral foramen. Intervertibral foramen is an opening between the vertebras that serves as passage of nerves that come out of spinal cord to supply the various body parts. There are seven processes that arise from the vertebral arch at the point where the lamina and pedicle joins. 83 Human Anatomy and Physiology The transverse processes on both side extends laterally. The Spinous processes extends posteriorly & inferiorly from the junction of the laminae. Both the transverse & spinous processes are muscle attachments. The remaining four processes form joints with other vertebra. Two of them articulate with the immediate superior vertebra. And the other two articulate with the immediate inferior vertebra. Figure: 5.11 Typical vertebra (source: Carola, R., Harley,J.P., Noback R.C., nd (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2 ed, pp 188) 84 Human Anatomy and Physiology Table 5.5 Description and function of bones of the vertebral column (26 bones), (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2nd ed, pp 187) Bones Description and function Cervical vertebrae (7) First (atlas), second (axis), and seventh vertebrae are C1-C7 modified; third through sixth are typical; all contain transverse formina. Atlas supports head, permits "yes" motion of head at joint between skull and atlas; axis Permits "no" motion at joint between axis and atlas. Thoracic vertebrae (12) Bodies and transverse processes have facets that articulate T1-T12 with ribs; laminae are short, thick, and broad. Articulate with ribs; allow some movement of spine in thoracic area. Lumbar vertebrae(5) Largest, strongest vertebrae; adapted for attachment of back L1-L5 muscles. Support back mus cles; allow forward and backward bending of spine. Sacrum Wedge-shaped, made up of five fused bodies united by four (5 fused bones) intervertebral disks. Support vertebral column; give strength and stability to pelvis. Coccyx Triangular tailbone, united with sacrum by intervertebral (3 to 5 fused bones) disk. Vestige of an embryonic tail. In a child there are 33 separate vertebrae, the 9 in the sacrum and coccyx not yet being fused. 85 Human Anatomy and Physiology The Thorax Refers to the chest. Thorax is a bony cage formed by sternum (breast bone), costal cartilage, ribs and bodies of the thoracic vertebra. Figure: 5.12 Skeleton of the thorax (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, nd New York, 2 ed, pp 193) Sternum (breast bone) Sternum is flat, narrow bone measuring about 15 c.m. (6 inch) located in the median line of anterior thoracic wall. It consists 3 basic portions: the manubrium (superior portion), the body (middle & largest portion) and the xiphoid process (inferior & smallest portion). The junction of the manubrium and the body forms the sternal angle. The manubrium on its superior portion has a depression called jugular (supra sternal) notch. 86 Human Anatomy and Physiology On each side of the jugular notch are clavicular notch that articulates with medial end of clavicle. The manubrium also articulates with the 1st and 2nd rib. The body of the sternum articulates directly or indirectly with 2nd to 10th rib. The xiphoid process consists hyaline cartilage during infancy and child hood and do not ossify completely up to the age of 40. Figure: 5.13 The ribs and sternum ( source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, nd New York, 2 ed, pp 194) 87 Human Anatomy and Physiology Ribs Human being contains 12 Pair of ribs that make up the side of thoracic cavity. Ribs increase in length from 1st through 7th and they decrease in length through 12th. Each ribs posteriorly articulates with the body of its corresponding thoracic vertebra. Anteriorly the 1st seven ribs have direct attachment to sternum by costal cartilage hence they are called true (vertebro – sternal) ribs. The remaining 5 ribs are called false ribs. The 8th – 10th ribs, which are groups of the false ribs are called vertebro chondrial ribs because their cartilage attach one another and then attaches to the cartilage of the 7th rib. The 11th & 12th ribs are designated as floating ribs because their anterior part even doesn't attach indirectly to sternum. Although there is variation when we examine a typical rib (3rd to 9th) contains a head, neck and body parts. The Head is a projection at posterior end of the rib. It consist one or two facet that articulate with facet of the vertebra. The neck is constricted portion just lateral to the head. One or two knob like structures on the posterior end where the neck joins the body is the tubercles, which articulate with the 88 Human Anatomy and Physiology transverse process of the vertebra and to attach with muscles of the trunk. The body (shaft) is main part of the rib.. The costal angle is the site where the rib changes its direction. The inner side of the costal angle is costal grove. Where thoracic nerves and blood vessels are protected. 5.2.4 The Appendicular skeleton The upper extremities (limbs) The upper extremities consists of 64 bones. Connected and supported by the axial skeleton with only shoulder joint and many muscle from a complex of suspension bands from the vertebral column, ribs and sternum to the shoulder girdle. 89 Human Anatomy and Physiology Figure: 5.14 The upper extremity (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, nd 2 ed, pp 204) 90 Human Anatomy and Physiology Figure: 5.15 Shoulder girdle (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, nd 2 ed, pp 205) 91 Human Anatomy and Physiology Table 5.6: Description and function of bones of the upper extremity (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, New York, 2nd ed, pp 204) Bone Description and function Shoulder (Pectoral) Girdle CLAVICLE (2) Collarbone; double-curved, long bone with rounded medial end and flattened lateral end; held in place by ligaments. Holds shoulder joint and arm away from thorax so upper limb can swing freely. Scapula (2) Shoulder blade; flat, triangular bone with horizontal spine separating fossae. Site of attachment for muscles of arm and chest. Arm Humerus (2) Longest, largest bone of upper limb; forms ball of ball- and socket joint with glenoid fossa of scapula. Site of attachment for muscles of shoulder and arm, permitting arm to flex and extend at elbow. Forearm Radius (2) Larger of two bones in forearm; large proximal end consists of olecranon process (prominence of elbow). Forms hinge joint at elbow. Wrist Carpals (16) Small short bones; in each wrist, 8 carpals in 2 transverse rows of 4. With attached ligaments, allow slight gliding movement. Hands and Fingers Metacarpals (10) Five miniature long bones in each hand in fanlike arrangement; articulate with fingers at metacarpo- phalangeal joint (the Knuckle). Aid opposition movement of thumb; enable cupping of hand. 92 Human Anatomy and Physiology Phalanges (28) Miniature long bones, 2 in each thumb, 3 in each finger; articulate with each other at interphalangeal joint. Allow fingers to participate in stable grips. Figure: 5.16 Humerus, radius and ulna (source: Elaine n. MARIEB, (2000), Essentials of human anatomy and physiology, Addison welsey th longman inc., San Francisco, 6 Ed) 93 Human Anatomy and Physiology Figure: 5.17 Bones of the hand (source: Memmler, Ruth Lundeen, Barbara Jansen Cohen and Dena Lin Wood (1996), The Human Body in th Health and Disease, 8 Ed, pp 100) The lower extremity It consist 62 bones. The lower extremity is connected to the axial skeleton with the hip girdle. 94 Human Anatomy and Physiology Figure: 5.18 The lower extremity (source: Carola, R., Harley,J.P., Noback R.C., (1992), Human anatomy and physiology, Mc Graw hill inc, Ne