Week 1 PMS (1) PDF

Pr. Sayed Anwar Sayed Hasan Overview and introduction to anatomy Learning objectives: 1-know the anatomical position and term. 2-know the different types of movements. 3-Describe in simple terms the normal structure of tissues , organs and systems. 4-Apply knowledge to understand t...

Pr. Sayed Anwar Sayed Hasan Overview and introduction to anatomy Learning objectives: 1-know the anatomical position and term. 2-know the different types of movements. 3-Describe in simple terms the normal structure of tissues , organs and systems. 4-Apply knowledge to understand the function of human body Anatomy is the study of the structure of the body, the Latin word anatomy (ana= through, tom = cut) means to dissect or to cut a part. THE ANATOMICAL POSITION - This position is used as a standard reference throughout the medical profession. - This is true regardless of what position the body is actually in. The anatomical position is described as follows: a- The body stands erect, with heels together. b- Upper limbs are along the sides, with the palms of the hands facing forward. c- The head faces forward. METHODS OF STUDYING ANATOMY Human anatomy can be studied by two methods: (1)Systematic anatomy: The various structures may be Anatomical position separately considered. (2)Topographical or regional anatomy: The organs and tissues may be studied in relation to one another. SYSTEMATIC ANATOMY It includes the following branches Osteology: The bony system or skeleton. Syndesmology: The articulations or joints. Methods of studying anatomy 1 Pr. Sayed Anwar Sayed Hasan SYSTEMATIC ANATOMY Myology: The muscles. Angiology: The vascular system, comprising the heart, blood vessels, lymphatic vessels, and lymph glands. Neurology: The nervous system. The organs of sense may be included in this system. Splanchnology: The visceral system. Topographically the viscera form two groups, viz., the thoracic viscera and the abdomino-pelvic viscera. The heart, a thoracic viscera, is best considered with the vascular system. The rest of the viscera may be grouped according to their functions (a) The respiratory apparatus; (b) The digestive apparatus; and (c) The urogenital apparatus. REGIONAL ANATOMY REGIONS OF THE HUMAN BODY The human body is a single, total composite. Everything works together. Each part acts in association with ALL other parts. Yet, it is also a series of regions. Each region is responsible for certain body activities. These regions are: a. The trunk. includes the thorax (chest) and abdomen. At the lower end of the trunk is the pelvis. The perineum is the portion of the floor of the pelvis. The lungs, the heart, and the digestive system are found in the trunk. b. Head and Neck. The brain, eyes, ears, mouth, pharynx, and larynx are found in this region. 2 Pr. Sayed Anwar Sayed Hasan c. Limbs: 1. Each upper limb includes a shoulder, arm, forearm, wrist, and hand. 2. Each lower limb includes a hip, thigh, leg, ankle, and foot. REGIONAL ANATOMY Parts of the body 3 Pr. Sayed Anwar Sayed Hasan THE ANATOMICAL PLANES a. Sagittal planes are vertical planes that pass through the body from front to back. The median or midsagittal plane is the vertical plane that divides the body into right and left halves. b. Horizontal (transverse) planes are parallel to the floor that divides the body into upper and lower parts. They are perpendicular to both the sagittal and frontal planes. c. Frontal (coronal) planes are vertical planes which pass through the body from side to side and divides the body into anterior and posterior parts. They are perpendicular to the sagittal plane. THE ANATOMICAL PLANES TERMS OF POSITION A) Superior, Inferior: Superior means nearer to the head. Inferior means farer from the head or nearer to the feet. 4 Pr. Sayed Anwar Sayed Hasan B) Anterior, Posterior: Anterior (or ventral) means nearer to the front of the body. Posterior (or dorsal) means nearer to the back of the body. C) Medial, Lateral: Medial means toward or nearer the midline of the body. Lateral means away from the midline of the body. Anatomical planes, terms of position and terms of movements 5 Pr. Sayed Anwar Sayed Hasan D) Superficial, Deep:Superficial means closer to the surface of the body. Deep means toward the center of the body or body part. E) Proximal, Distal: Proximal and distal are terms applied specifically to the limbs. Proximal means nearer to the shoulder joint or the hip joint. Distal means further away from the shoulder joint or the hip joint. Sometimes proximal and distal are used to identify the "beginning" and "end" of the gut tract—that portion closer to the stomach being proximal while that further away being distal. TERMS OF POSITION TERMS OF MOVEMENT Movements of the trunk in the sagittal plane are known as flexion (bending anteriorly) and extension (straightening or bending posteriorly). In the limbs, flexion is the movement which carry the limb anteriorly and fold it while extension is the movement which carry it posteriorly and straightens it. Flexion generally involves movement in an anterior direction; however, flexion at the knee joint involves posterior movement. 6 Pr. Sayed Anwar Sayed Hasan Terms of movements Dorsiflexion describes flexion at the ankle joint, as occurs when walking uphill or lifting the toes off the ground. Plantar flexion turns the foot or toes toward the plantar surface (e.g., when standing on your toes). Movement of the trunk in the coronal plane are known as lateral flexion while in the limbs they are called abduction (movement away from the median plane) and adduction (movement toward the median plane). In the fingers and toes, adduction is applied to the spreading and adduction is applied to drawing together of these structures. In the hand this movement is away from or toward the line of the middle finger, in the foot it is away from or toward the line of the second toe. Circumduction is a circular movement that is a combination of flexion, extension, abduction, and adduction occurring in such a way that the distal end of the part moves in circle. Circumduction can occur at any joint at which all the above-mentioned movements are possible (e.g., Shoulder and hip joints). 7 Pr. Sayed Anwar Sayed Hasan Rotation involves turning or revolving a part of the body around its longitudinal axis, such as turning one's head to face sideways. Medial rotation (internal rotation) brings the anterior surface of a limb closer to the median plane, whereas Lateral rotation (external rotation) takes the anterior surface away from the median plane. Terms of movements Pronation is the rotational movement of the forearm and hand that swings the radius (the lateral long bone of the forearm) medially around its longitudinal axis so that the palm of the hand faces posteriorly and its dorsum faces anteriorly. When the elbow joint is flexed, pronation moves the hand so that the palm faces inferiorly (e.g., placing the palms flat on a table). Supination is the rotational movement of the forearm and hand that swings the radius laterally around its longitudinal axis so that the dorsum of the hand faces posteriorly and 8 Pr. Sayed Anwar Sayed Hasan the palm faces anteriorly (i.e., moving them into the anatomical position). When the elbow joint is flexed, supination moves the hand so that the palm faces superiorly. Opposition is the movement by which the pad of the 1st digit (thumb) is brought to another digit pad. This movement is used to pinch, button a shirt, and lift a teacup by the handle. Reposition describes the movement of the 1st digit opposition back to its anatomical position. Inversion: move the sole of the foot towards the midline. Eversion: move the sole of the foot away from the midline. Choose the correct answer 1-………. refers to the same side of the body A) Contralateral. B) Ipsilateral. C) Lateral. D)Medial. E) Proximal. 2- ………… is a structure situated nearer to the median plane of the body than another is said to be A) Distal. B) Lateral. C) Medial. D) Proximal. E) Superior. 3- ……………is any structure nearer to the back of the body. A) Anterior. B) Distal. C) Posterior. D) Proximal. E) Superior. 9 Pr. Sayed Anwar Sayed Hasan Lecture (2) Covering of the body Learning objectives: After this lecture, student should be able to: - Know the structure of the skin. - Know the appendages of the skin (Nails, Hairs, sebaceous glands, sweat glands). - Describe the cleavage lines of the skin. - Know the structure and function of fascia. - Know the division of fascia (superficial and deep fasciae) - Know fascial planes, fascial compartments and potential spaces. - Understand important clinical conditions e.g. skin incisions, skin infections, sebaceous cyst, burns and fascia and infections. THE INTEGUMENT PROPER (SKIN) The integument proper is the outermost layer of the human body. It is usually known as the skin. The skin has two layers (a) Superficial or outer layer called the epidermis (b) Deeper or inner layer called the dermis. The skin 1 Pr. Sayed Anwar Sayed Hasan a. The Epidermis: The epidermis is a stratified squamous epithelium. This means that it is made up of several layers of cells, the outermost being flat-type epithelial cells. (1) The outer layers of the epidermis include cells which are transparent, flattened, dead, and without nuclei. These hardened cells of the outermost layers are completely filled with keratin and are known as cornified cells. These dead flat cells in the outermost layers resemble scales. Day by day, these cells are scraped away or just fall away from the body. They are replaced by cells from the intermediate layers. (2) In the intermediate layers of the epidermis, the cells change their shapes. As the cells move towards the surface, they gain granules, begin to manufacture a hardening material called keratin, and lose their nuclei. (3) The innermost layer of the epidermis is especially important because it is the source of all the other layers of the epidermis. It is known as the basal or germinative layer. The cells of this layer are capable of multiplication (mitosis). b. The Dermis (Dermal Layer) is the layer of the skin lying just beneath the epidermis. It is dense fibrous connective tissue consisting of white and yellow fibers. The dermis has finger-like projections called papillae. These papillae extend into the epidermis and keep the dermis and epidermis from sliding on each other. The dermal layer includes blood vessels, lymph vessels, nerve endings, hair follicles and gland. 2 Pr. Sayed Anwar Sayed Hasan INTEGUMENTARY DERIVATIVES The integumentary derivatives are formed from the tissues of the integument proper (dermis and epidermis). All are appended (attached) to the integument proper and are often known as the appendages of the skin. These include the glands, hairs, and nails associate with the skin. HAIRS ♦Hairs are distributed over the whole surface of the body except the lips, the palms of the hands, the sides of the fingers, some areas of external genitalia and the soles and sides of the feet and the sides of the toes. ♦Hair follicle is formed by the extension of the skin (dermis and epidermis) deeper into the surface of the body. Follicles may extend into the subcutaneous layer. ♦At the base of the hair follicle is the hair root. The hair shaft grows out from the root. The hair shaft is made of cells from the outermost layers of the epidermis. ♦Scalp and facial hairs grow continuously. Other hairs of the body grow to fixed lengths. The types and patterns of hairs are determined for each individual by genetics, including his/her sex. GLANDS The types of glands included are the sweat glands and the sebaceous (fat/ oil) glands. 3 Pr. Sayed Anwar Sayed Hasan 1-Sweat Glands: consist of a coiled secretory portion and a wavy duct which leads to the surface of the skin. The coiled secretory portion is located in the dermis or deeper. Sweat glands are distributed over the surface of the body except the red margins of the lips, the nail beds, external ear canal, and the glans penis and clitoris. 2- Sebaceous Glands: produce an oily substance which lubricates the skin and hairs. The oil keeps the skin and hairs flexible. The sebaceous glands are usually found as a part of the walls of hair follicles and their oil flows into the follicle. In a few places without hairs, they open directly to the skin surface. ♦ NAILS: are found on the ends of the digits (fingers, and toes). Nails help to protect the ends of these digits. Each nail bed is attached to the top of the terminal phalanx (bone) of each digit. The nail itself is made up of cornified (hardened) outer cell layers of the epidermis. The nails grow continuously from their roots. SKIN COLORATION The skin includes red, black, and yellow pigments. The proportions of these pigments determine the skin color. This proportion is determined by genetics. The absence of all pigments is called albinism. In albinism, white light is reflected and a pink hue results from the color of the blood shining through the transparent skin. 4 Pr. Sayed Anwar Sayed Hasan THE SUPERFICIAL FASCIA ♦The superficial fascia is the second envelope of the body. It is the layer between the skin and the investing deep fascial envelope. It is often called subcutaneous layer. ♦The superficial fascia is made up primarily of loose areolar fatty tissue with the spaces filled by fatty tissue and tissue fluid. ♦The thickness of the superficial fascia is more in females (secondary sex character). It varies from one person to another and from region to another with the amount of fat in its meshes. ♦It is thickest in the anterior abdominal wall, where it is differentiated into two layers superficial fatty layer and deep membranous layer. ♦It is thinnest in the eye lids and the nipples of the breast and in some parts of the external genitalia where there is no fat. ♦It contains superficial or cutaneous branches of nerves, arteries, veins, and lymphatics of the skin. In some regions it contains muscles such as the scrotum (dartos muscle) and the neck (platysma muscle). In the pectoral region it contains the mammary gland. ♦The fat in the superficial fascia acts as an insulator helping in regulation of body temperature, giving the body its contour and allowing movement of the skin on the underling structure. 5 Pr. Sayed Anwar Sayed Hasan Platysma muscle Mammary gland Mammary Glands: In the adult human female, the mammary gland lies in the subcutaneous layer anterior to the chest muscle (pectoralis major M.). Its function is to nourish the newborn. A nipple is located near the center of each breast. Around each nipple is a darkened area known as the areola. The tip of the nipple has many small openings to allow the passage of the milk from the milk ducts. These ducts are connected to lobes of glandular tissue located throughout the breast. Fat and fibrous connective tissue fills in the spaces among the lobes. The fat in the superficial fascia acts as an insulator helping in regulation of body temperature, giving the body its contour and allowing movement of the skin on the underling structure. Mammary gland 6 Pr. Sayed Anwar Sayed Hasan THE DEEP FASCIA (a) The deep fascia envelops the entire body as the third envelope. This third envelope is known as the investing deep fascia. It is beneath the skin and subcutaneous layer. (b) Deep fascia also includes the envelopes of the muscles (sheath )and other organs. Around individual organs (for example, the kidney), it is called a capsule. (c) It sends partitions or septa between the muscles (intermuscular septa) and ensheathes the blood vessels and nerves between them. These partitions form a major part of the attachment of many muscles. (d) In some regions (distal joints), the deep fascia is thickened to form retinacula that hold the tendons in position and form pulley within which the tendons slide where they change direction e.g : at wrist (flexor and extensor retinacula) and ankle (flexor, extensor and peroneal retinacula). (e) Another form of deep fascia is found in the collections of loose areolar CT and fat that are found as filling among the organs. Similar deep fasciae attach organs to the body wall. 7 Pr. Sayed Anwar Sayed Hasan Retinacula Concerning the skin all are true EXCEPT: a. It covers the body surface. b. It regulates body temperature. c. The dermis is the outer layer. d. The epidermis is avascular layer. Regarding the deep fascia, choose one false statement: a. It is thickened in the palm of hand. b. It is thickened in the abdomen allowing it to change its volume. c. It forms sheath for muscles. d. It sends intermuscular septa. 8 Faculty of Medicine Histology Department HISTOLOGY AND ITS METHODS OF STUDY Lecture 3 In Block 102PMS Prepared by Prof. Amel Marzouk Edited by Dr. Asmaa Youssef Histology Department Faculty of Medicine Assiut University 2023-2024 1  Histology and its Methods of study Learning objectives (Lecture 3) After the lecture, students should be able to: Define histology. Identify the methods of studying cells and tissues. Recognize the light and electron microscopes. Know the cell and tissue culture. Histology is the study of the microscopic structure of cells, tissues and organs of the body, with the focus on how cells' structure and arrangement adapt to perform functions specific to each organ. Tissues have two interacting components: cells and extracellular matrix (ECM). The ECM supports the cells and contains the fluid transporting nutrients to the cells and carrying away their wastes and secretory products. Methods of Studying Cells and Tissues *Several methods are used to study cells and tissues most commonly including: -Microscopic approaches (light & electron microscopes). -Tissue culture. 2  Microscopic approaches Preparation of tissues for microscopic study **For microscopic examination of the tissue;  Tissue sections must be preserved so that the tissue examined by the microscope has the same structural features it had in the body.  Thin stained tissue sections must be prepared. Basic steps of tissue preparation for microscopic examination 3 Examples of tissue sections prepared for microscopic examination: A) Paraffin sections: The fixed tissue is embedded in melted paraffin wax (52 °- 60°). This makes the tissue hard enough to be cut into thin sections. Microtome used for obtaining paraffin sections This is the most common type of tissue sections for light microscopic examination (LM). However, in this procedure, the tissue is exposed to high temperature which dissolves cell lipids, inactivates most sensitive tissue enzymes. B) Frozen sections: It is a much more rapid processing method for LM. The tissue is rapidly frozen in liquid nitrogen (- 195° C), preserving cell structures and hardening the tissue. Frozen sections are effective in histochemical study of very sensitive enzymes and in study of lipids because freezing preserves cell enzymes and lipids. C) Plastic sections: It is used to prepare ultrathin plastic-embedded tissue sections for electron microscopic examination (EM). 4 Staining Most cells and extracellular matrix components are colorless and to be studied microscopically, tissue sections must be stained. Staining methods make various tissue components visible and distinguishable from one another when examined by the microscope. Main Types of staining methods for LM: 1. General Staining Methods: are used to reveal general structural features of the tissue. The most common general stain used is the combination of hematoxylin and eosin (H&E): -Hematoxylin is a basic dye which stains acidic cell components such as nucleic acids (DNA &RNA). The cell components which have an affinity for basic dyes are termed basophilic. -Eosin is an acidic dye which stains basic cell components such as most cytoplasmic membranous components (e.g. mitochondria). The cell components which have an affinity for acidic dyes are termed acidophilic. 5 2. Special (= Selective) Staining Methods: are used to reveal certain cell and ECM components. For example: a. Orcein dye stains elastic fibers. b.Sudan black dye stains lipids. 3. Histochemical and Cytochemical Staining Methods: are specific chemical staining methods based on specific binding of the dye with a particular cell and ECM component. For example: - Periodic acid-Schiff (PAS) reaction stains carbohydrates (glycogen). 6  Microscopes *The microscope is an instrument having magnifying lenses for inspecting objects too small to be seen by the human eyes. *Any microscope serves TWO main functions; resolution and magnification. Magnification is of value ONLY when accompanied by high resolution. *Resolution is the power of the microscope to distinguish fine details. *Resolving power is defined as the smallest diameter of an object below which it cannot be distinguished with the microscope. It is also defined as the smallest distance between two particles at which they can be seen as separate objects.  Main Types of Microscopes: 1. Light microscopes are based on the passage of light through thin stained tissue sections. The maximal resolving power of the ordinary light microscope is approximately 0.2 µm which allows clear images magnified 1000 times. 2. Electron microscopes are based on the use of electron beams (instead of light). It has TWO main types: a. Transmission electron microscope is based on the passage of electron beams through ultrathin tissue sections to study fine tissue structures. It has resolving power as little as 1 nm which allows clear images magnified as much as 100,000 times. b.Scanning electron microscope: The electron beam scans the surfaces of cells, tissues and organs, providing a three dimensional (3D) image. 7 Parts of light microscope 8  Cell and Tissue Culture *Definition: is the maintenance and study of live cells and tissues outside the body in culture (in vitro). *Uses: 1. Cell culture allows the direct observation of cellular behavior. 2. Experiments which are technically impossible to perform in the body (in vivo) can be accomplished in culture (in vitro). 3. Genetic or chromosomal analyses. 4. Study of molecular changes in cancer. Lecture References: -Kaplan Medical, USMLE Step 1 Lecture Notes, Pathology, 2021, P. 1-2 - Elsevie r’s integrated Histology: 1st edition p. 1-12) -Junqueira's Basic Histology: Text and Atlas 14th Edition. 9  Self Assessment of Lecture 3 I- Complete the missing words:. Examples of tissue sections are.............................….and.................………. The most common general stain used is…………………………….……….... …………….provides a three dimensional (3D) image of cells, tissues and organs.. Resolving power is defined as………………………………………. II- Answer true (T) or false (F): -Most tissues can be studied directly by the microscope ( ) -Hematoxylin is an acidic dye which stains basic cell components ( ) -Sudan black dye stains lipid-rich tissue structures ( ) III- Choose the correct answer:.........................is based on the passage of electron beams through the tissue: a- Light microscope. b- Electron microscope. c- Acidic stains. d- Cell culture. 2. To study chromosomal analyses, we use: a- Fixed tissue. b- In vivo studies. c- Cell culture. d- Sudan black stain. 10 Faculty of Medicine Histology Department PLASMA MEMBRANE Lecture 4 In Block 102PMS Prepared by Dr/ Amel Marzouk Edited by Dr/ Marwa Hassan Bakr Histology Department Faculty of Medicine Assiut University 2023-2024 Plasma Membrane Learning objectives (Lecture 4) After the lecture, students should be able to: ▪ Identify the components of the cell. ▪ Describe the structure of plasma membrane. ▪ Recognize the role of transmembrane proteins in membrane transport. 1 ▪ Identify endocytosis & exocytosis. Cells are the structural and functional units (the smallest living parts) of the body. *Cells can be eukaryotic or prokaryotic: Eukaryotic cells (eu = true) (e.g. human & animal cells): a. Are larger than prokaryotic cells. b. Have plasma membrane that defines the outer limit of the cell. c. Have a definite membrane-limited nucleus. d. Their cytoplasm contains membrane-limited organelles. Prokaryotic cells (karyo = nucleus) (e.g. bacteria): a. Are smaller cells. b. Have cell wall outer to the plasma membrane. c. Lack nuclei. d. Lack membrane-limited organelles. 2  Plasma Membrane *The plasma membrane (also called plasmalemma) envelops every eukaryotic cell & defines its outer limit. *Membranes range from 7.5-10 nm in thickness and so, they are visible ONLY in the electron microscope (E.M.). *With E.M., the plasma membrane has a trilaminar appearance with two dark outer lines enclosing a light band in between. 3 *Plasma membrane consists of lipids, proteins and carbohydrates. Membrane Lipids Plasma membrane has phospholipids & cholesterol as their major lipid components: 1. Phospholipids are organized into a double layer (bilayer) with their hydrophilic heads form each membrane surface and their hydrophobic chains located in the middle of the membrane. 2. Cholesterol molecules insert among the closely packed phospholipids, restricting the movement of phospholipids. *Some lipid molecules have externally exposed oligosaccharide chains forming glycolipids which contribute to the cell's glycocalyx. 4  Membrane Proteins There are two types of proteins in the plasma membrane: 1. Integral proteins are directly incorporated within the phospholipid bilayer. When these proteins completely span the bilayer, they are called transmembrane proteins. 2. Peripheral proteins are loosely associated with one of the two membrane surfaces, particularly on the cytoplasmic side. *Some protein molecules have externally exposed oligosaccharide chains forming glycoproteins which contribute to the cell's glycocalyx. Membrane Carbohydrates Are oligosaccharide chains linked to lipid & protein molecules and extend outward from the plasma membrane forming the cell’s glycocalyx. 5 What is the cell's glycocalyx (cell coat)? It is a delicate cell surface coating. It is formed of oligosaccharide chains attached to both lipid and protein components of plasma membrane and exposed at the external membrane surface. Functions of the cell coat: It binds antigens and enzymes to the cell surface It facilitates cell–cell recognition and interaction. Transmembrane Proteins & Membrane Transport The plasma membrane is the site where materials are exchanged between the cell and extracellular matrix (ECM). Some substances (fat-soluble and small, uncharged molecules) cross the plasma membrane by simple diffusion down their concentration gradient 6  Membrane proteins serve as selective gateways for most small molecules entering the cell through: a. Ion Channels are transmembrane proteins forming pores through which ions such as Na+, K+ and Ca2+ pass selectively. b. Carriers are transmembrane proteins that bind specific molecules & deliver them to the other side of the membrane. Exocytosis & Endocytosis *Exocytosis: Means bulk movement of macromolecules out of the cell by fusion of secretory vesicles with the plasma membrane. *Endocytosis: Means bulk movement of macromolecules into the cell by formation of vesicles at the plasma membrane. Endocytosis includes: 7 1. Phagocytosis: Is a type of endocytosis meaning the ingestion of particles (cell eating). 2. Pinocytosis: Is a type of endocytosis in which extracellular fluid is taken up by the cell (cell drinking). 8  Identify process (a) & process (b) Process (a) is ……………………………………… Process (b) is ……………………………………… Lecture References: -Junqueira's Basic Histology: Text and Atlas 16th Edition. 9  Self-Assessment of Lecture 4 I- Complete the missing words: 1. The cell lacking nuclei and membrane-limited organelles is ……………………. cell. 2. Oligosaccharide chains of glycolipids & glycoproteins constitute the …….………… II- Choose the correct answer: 1. Bulk movement of macromolecules into the cell by formation of vesicles is: a- Exocytosis. b- Endocytosis. c- Receptors. d- Channels. 2. …………….. is loosely associated with one of the two membrane surfaces, particularly on the cytoplasmic side: a- Lipid bilayer. b- Cholesterol. c- Integral protein. d- Peripheral protein. 10 Pr. Sayed Anwar Sayed Hasan Lecture (5) MUSCLES Learning objectives: After this lecture, student should be able to: 1-know the different types of muscles. 2-know the different types of muscle origins and insertions. 3- Describe the shape and arrangement of muscle fibers. 4-Describe the major muscles of the body. 5- Understand the mechanism of muscle action. 6-Understand the role of muscles in muscle tone. DEFINITION: Muscles are the red flesh of the body they are tissues specialized to produce motion by contraction. Types of muscles TYPES: a. Smooth muscle tissue makes up the muscular portion of the various visceral organs. They are not under the control of will. They are non stripped muscle. Examples of this type are muscles of stomach, blood vessels intestine, uterus and urinary bladder. b. Cardiac muscle tissue makes up the muscular wall of the heart- the myocardium. They are involuntary and partially stripped. c. Skeletal (voluntary) muscles are attached to and moves bones. They are stripped (striated) and under the control of will. Examples of skeletal muscles are muscles of limbs. 1 Pr. Sayed Anwar Sayed Hasan ………….. is an interdigitation of the tendinous ends of fibers of flat muscles. a) Aponeurosis. b)Tendon c) Raphe d)origin Characteristics of muscles General Construction of a Skeletal Muscle ♦The large portion of a muscle is known as its belly or fleshy belly. This muscle is attached to bones by tendons or aponeuroses. ♦Tendons and aponeuroses are similar to each other. However, tendons are cord-like and aponeuroses are broad and flat. ♦The fleshy portion may be directly connected to the bone. Each muscle is usually attached to the skeleton by two points, a fixed proximal point (origin) and a movable distal one (insertion). 2 Pr. Sayed Anwar Sayed Hasan Tendon versus aponeurosis Muscular Nerves, Arteries, Veins, Lymphatics (1) From the main nerve, artery, vein, lymphatic, there are branches going to each muscle. These muscular branches are bound together by a fibrous connective tissue sheath to form a neurovascular bundle. (2) The motor point is that specific location on the surface of the muscle where the neurovascular bundle enters. (3) A motor unit is the single motor neuron and the number of striated muscle fibers activated by it (innervation). A neurovascular bundle 3 Pr. Sayed Anwar Sayed Hasan Nerve supply of muscles ♦ MUSCLE FORMS This refers to the arrangement of the fibers of the muscles with reference to the tendons to which they are attached. (1)Parallel (a) Quadrilateral muscles: the fibers run directly from their origin to their insertion such as the Thyrohyoid. (b) Fusiform muscles: the fibers are not quite parallel, but slightly curved, so that the muscle tapers at either end; such as biceps brachii. (c) Strap: fibers are parallel forming a thin sheet such as Sartorius. (2) Triangular The fibers are convergent; arising by a broad origin, they converge to a narrow or pointed insertion. e.g., the temporalis Parallel muscle form 4 Pr. Sayed Anwar Sayed Hasan (3) Pennate They resemble a feather in which the fibers are oblique to the long axis of the muscle. (a) Unipennate :the fibers are located to one side of a tendon which runs the entire length of the muscle such as palmar interossei. (b) Bipennate : where oblique fibers converge to both sides of a central tendon; an example is the Rectus femoris. (c) Multipennate where oblique fibers converge to both sides of Multiple central tendons ; such as deltoid muscle. (d) Circumpennate fibers are arranged in a circumradial manner around the central tendon an example is tibialis anterior muscle. 5 Pr. Sayed Anwar Sayed Hasan MUSCLE NAMES The names applied to the various muscles have been derived: (1) From their situation, as the Tibialis, Radialis, Ulnaris. (2) From their direction, as the Rectus abdominis, Obliqus abdominis,Transversus abdominis. (3) From their uses, as Flexors, Extensors, Abductors. (4) From their shape, as the Deltoideus, Rhomboideus. (5) From the number oftheir divisions, as the Biceps and Triceps. (6)From their points of attachment, as the sternocleidomastoideus, Sternohyoideus Skeletal Muscle Action: Prime mover: A muscle is a prime mover when it is the chief muscle or member of a chief group of muscles responsible for a particular movement. For example, the quadriceps femoris is a prime mover in the movement of extending the knee joint. Antagonist: Any muscle that opposes the action of the prime mover is an antagonist. For example, the biceps femoris opposes the action of the quadriceps femoris when the knee joint is extended. Before a prime mover can contract, the antagonist muscle must be equally relaxed; this is brought about by nervous reflex inhibition. 6 Pr. Sayed Anwar Sayed Hasan Fixator: A fixator contracts isometrically (i.e., contraction increases the tone but does not in itself produce movement) to stabilize the origin of the prime mover so that it can act efficiently. For example, the muscles attaching the shoulder girdle to the trunk contract as fixators to allow the deltoid to act on the shoulder joint. Synergist: In many locations in the body the prime mover muscle crosses several joints before it reaches the joint at which its main action takes place. To prevent unwanted movements in an intermediate joint, groups of muscles called synergists contract and stabilize the intermediate joints. For example, the flexor and extensor. Fixator Synergist Nerve Supply of Skeletal Muscle: The nerve trunk to a muscle is a mixed nerve, about 60% is motor and 40% is sensory, and it also contains some sympathetic autonomic fibers. The nerve enters the muscle at about the midpoint on its deep surface, often near the margin; the place of entrance is known as the motor point. This arrangement allows the muscle to move with minimum interference with the nerve trunk. 7 Pr. Sayed Anwar Sayed Hasan Choose the correct answer: -…………….. complements the action of prime movers. A) Fixator B) Agonist C) Synergist. D) Antagonist -………………… is a muscle that opposes the action of a prime mover. A) Fixator B) Agonist C) Synergist D) Antagonist -………………have two rows of muscle fibers, facing in opposite diagonal directions, with a central tendon, like a feather. A) Bipennate. B) Fusiform. C) Unipennate D) Parallel. 8 MEMBRANOUS ORGANELLES Lecture 6&7 In Block 102PMS Prepared by Prof. Nashwa Ahmed Mohamed Department of Histology Faculty of Medicine Assiut University 2022-2023 1 Learning objectives (Lectures 6&7) After the lecture, students should be able to: Define cell organelles and classify them. Identify the types (smooth and rough), structure & function of the endoplasmic reticulum. Discuss the structure & function of Golgi bodies. Recognize the structure & types of lysosomes. Discriminate the structure & function of peroxisomes. Describe the structure of mitochondria. 2  Cell organelles A-Membranous organelles - Rough & smooth endoplasmic reticulum - Golgi apparatus - Lysosomes - Microbodies (peroxisomes) - Mitochondria B-Non membranous organelles - Ribosomes, - Proteasomes, - Centrosomes, - Cytoskeleton, which includes microfilaments, intermediate filaments & microtubules. 3  Endoplasmic Reticulum The endoplasmic reticulum (ER) is an extensive network of intracellular membranes. Types: The ER is classified into two major functional and morphologic categories: 1- The rough endoplasmic reticulum ( rER). 2- The smooth endoplasmic reticulum (sER). 4 Smooth endoplasmic reticulum (SER) Regions of ER that lack ribosomes make up the smooth endoplasmic reticulum (SER). It contains enzymes associated with a wide variety of specialized functions. * The sER is well developed in cells that synthesize and secrete steroids and therefore is highly developed in cells of the adrenal cortex and steroid secreting cells of the ovaries and testes. Hepatocytes also have a highly developed SER, as they are constantly detoxifying hydrophobic compounds through conjugation and excretion. * In skeletal and cardiac muscle, the sER is called the sarcoplasmic reticulum. LM: cells rich in SER are highly acidophilic due to the absence of ribosomes on their membrane. EM: it appears as membrane-bound tubules &vesicles with no ribosomes on their surfaces. 8 Functions: 1- Lipid synthesis (especially steroids), e.g., adrenal cortex cells and interstitial cells of the testis. The smooth endoplasmic reticulum (SER) is the site of fatty acid and phospholipid production. 2-Detoxification of drugs. e.g., cells of the liver 3- Helps muscular contraction ( by sequester and release Ca2+) 4- Helps intracellular transport. 5- Glycogenolysis as in liver cells. 6- Mineral metabolism as in the parietal cell of the stomach. 9  Rough Endoplasmic reticulum (RER) They are flattened cisternae, The rough in rough endoplasmic reticulum comes from the many ribosomes that stud the membrane of the RER. Ribosomes associate with transfer RNA (tRNA) to translate messenger RNA (mRNA) into amino acid sequences and, eventually, into proteins. Proteins whose functional destiny is to become part of the plasma membrane, of the extracellular environment, or of certain intracellular organelles are synthesized by the endoplasmic reticulum. * The rER is most highly developed in active secretory cells. In those cells that synthesize proteins destined to leave the cell and in cells with large amounts of plasma membrane, such as neurons. Secretory cells include glandular cells such as pancreatic acinar cells and plasma cells. LM: it is highly basophilic due to the presence of ribosomes on its surface. All ribosomes contain RNA, that account for basophilic staining of the cytoplasm. *The large basophilic bodies of nerve cells, called Nissl bodies, consist of both rER and large numbers of free ribosomes. EM: it appears as membrane-bound cisternae with ribosomes on their surfaces and concentrated material in their lumens. In many instances, the rER is continuous with the outer membrane of the nuclear envelope. The function: The RER is the location of membrane and secretory protein production. 10  Golgi complex (Golgi apparatus) Golgi apparatus is a morphologically complex system of membrane vesicles and cisternae in which proteins and other molecules made in the ER undergo modification and maturation. They are sorted into specific vesicles for different roles in the cell. *The Golgi apparatus is well developed in secretory cells. It is active both in cells that secrete protein by exocytosis and in cells that synthesize large amounts of membrane and membrane-associated proteins such as nerve cells. LM: - The Golgi is seen as a light-staining or unstained area in the light microscope, usually near the nucleus. With H&E stain, secretory cells that have a large Golgi apparatus (e.g., plasma cells, osteoblasts, and cells of the epididymis) typically exhibit a clear area in the cytoplasm near the nucleus. -After silver or osmic impregnation, the Golgi appears as a dark structure taking different shapes and sites. Site: It is perinuclear (around the nucleus) in nerve cells, whereas in secretory cells, it lies between the nucleus and the secretory surface, and in liver cells, it is scattered in the cytoplasm. EM: The Golgi is formed of a series of stacked, flattened cisternae with dilated edges as well as small and large vesicles. -The array of cisternae is curved, giving the Golgi convex and concave sides. - There are 3-8 cisternae per Golgi depending on the activity of the cell. -The vesicles are of various sizes being larger at the concave (Trans-or maturation) surface and smaller at the convex (cis or formation) surface. -The small vesicles from RER and carry secretory material towards the formation surface. Functions: 1. It is the site for the condensation and packing of proteins that come from the rER. 2-Formation of lysosomes by packing hydrolytic enzymes. 11 3. In the Golgi, carbohydrates are added to proteins to form the proteoglycans. 4.The Golgi adds specific chemical groups to protein molecules (modification). 12  Lysosomes Lysosomes are small, membrane-bounded vesicles rich in hydrolytic enzymes. Lysosomes are considered the digestive apparatus of the cell. They are responsible for hydrolytic degradation of obsolete cellular components. Lysosomal enzymes (nucleases, proteases, and phosphatases) are active only at an acidic pH (between pH 4.5 and 5.0). To maintain this pH, the membrane of the lysosome contains a hydrogen ion pump, that generate an internal acid environment to function in hydrolysis of cell contents. Origin: from the Golgi region while their enzymes are synthesized in rER. *Lysosomes are particularly abundant in cells with great phagocytic activity (e.g., macrophages,neutrophils). LM: They are usually spherical can be demonstrated by special histochemical methods for detection of their enzymes (e.g. the acid phosphatase test). EM: Are membrane-bound vesicles. The primary lysosome presents a uniformly granular, electron-dense appearance. Types: 1- Primary lysosomes: are newly formed ones not yet engaged in any digestive activity. 2- Secondary lysosomes: are primary lysosomes that have been involved in the digestive activity. 3- Residual bodies: are secondary lysosomes containing indigestible materials. In some long-lived cells (e.g., neurons, heart muscle), residual bodies can accumulate over time as granules of lipofuscin. 11 Types of Lysosomes EM of lysosome 11 Functions: 1- Digestion of materials entering the cell either by phagocytosis (Extracellular large particles such as bacteria, cell debris, and other foreign ), pinocytosis and receptor- mediated endocytosis (Extracellular small particles) 2- Responsible for the disposal of worn-out or damaged cell components, e.g., old mitochondria (removal of nonfunctional organelles or excess cytoplasmic structures, a process called autophagy) 3-In some cells (e.g., osteoclasts involved in bone resorption and neutrophils involved in acute inflammation) may release lysosomal enzymes directly into the extracellular space to digest components of the extracellular matrix. *The absence of certain lysosomal enzymes can cause the pathologic accumulation of undigested substrates in residual bodies. This can lead to several disorders collectively termed lysosomal storage diseases. Microbodies (peroxisomes) Peroxisomes are another group of vesicular organelles found in the cytoplasm of cells.They are specialized to carry out oxidative reactions via a group of oxidative enzymes (oxidases) that utilize molecular O2 to produce H2O2. Excess H2O2 is removed by catalase, of which peroxisomes contain considerable quantities. The catalase (and general protein) concentration of the peroxisome is so high that it is often seen as a crystalline inclusion in the peroxisome, which can serve as a useful marker to recognize this organelle in electron micrographs. Peroxisomes contain no DNA or RNA and are self-replicating; new organelles arise by fission of preexisting organelles. They are numerous in liver cells. 11  Mitochondria (power houses of the cell) Mitochondria are membrane cytoplasmic-enclosed organelles. The shape of a typical mitochondrion is an elongated oval, but mitochondria may also be spherical, branched, coiled, or filamentous.When living cells are observed in tissue culture, mitochondria are highly dynamic—they are in constant motion and undergo fission and fusion. *Mitochondria are present in all cells except red blood cells and the outermost layers of the skin. The number of mitochondria is related to the cell's energy needs. Thus, cells with a high-energy metabolism (e.g., cardiac muscle, cells of some kidney tubules) have abundant mitochondria, whereas cells with a low-energy metabolism have few mitochondria. Mitochondria also localize at sites where energy is needed. In the middle piece of the sperm, the intermyofibrillar spaces in striated muscle cells, and adjacent to the basolateral plasma membrane infoldings in the cells of the proximal convoluted tubule of the kidney. Number in a specific cell type may range from 10 or 20 to thousands. 16  The main function of mitochondria is to provide energy, in the form of ATP, to drive the metabolic reactions of the cell. ATP is a major form of energy that the cell uses for nearly all its metabolic work. Mitochondria are also responsible for generating the heat that maintains body temperature. -LM: Mitochondria typically appear as numerous eosinophilic (red) structures in Hx.&E stain. Mitochondria contribute to the acidophilia of the cytoplasm because of the large amount of membrane they contain. Staining of mitochondria: a) Stained by special stain: iron haematoxylin. b) Vital stain: Janus green. c) Histochemical method by detection of cytochrome oxidase enzyme. EM. Mitochondria are surrounded by two membranes outer and inner membranes. Both mitochondrial membranes contain a higher density of protein molecules than other membranes in the cell. The outer membrane of the mitochondrion; next is an intermembrane space; then an inner mitochondrial membrane; and finally the mitochondrial matrix 1-The outer membrane is smooth. It is in contact with the cytoplasm of the cell. 2-The inner is thrown or folded into tubules called cristae or crests, which project into the matrix and greatly increase the membrane's surface area. The number of cristae in mitochondria also corresponds to the energy needs of the cell. This membrane is thinner than the outer mitochondrial membrane. The inner membrane of the cristae shows small particles known as elementary particles, which represent special ionic pores involved in electron transfer. New mitochondria originate by growth and division (fission) of preexisting mitochondria. Protein synthesis occurs in mitochondria, but because of the reduced amount of mitochondrial DNA, only a small subset of mitochondrial proteins is produced locally. 17 The innermost compartment, the mitochondrial matrix, contains the mitochondrial DNA, mitochondrial ribosomes, and enzymes of the tricarboxylic acid cycle and of fatty acid metabolism and mitochondrial transfer RNAs. Functions 1- Cell respiration and production of energy for the cell. 2- They can form proteins for themselves and undergo self-replication. (They have their DNA, ribosomes and can make their proteins) 18 References - Elsevier’s Integrated Histology (2007) 1st Edition. Page 19-24. -Lippincott Illustrated Reviews: Integrated Systems (2016), 24th ed. Page 41. - First aid for the Basic sciences, General principles. Third Edition. P: 3-5. 19  Self Assessment of Lectures 6&7 1- Function of RER is: a) Synthesis of fatty acids and lipids. b) Synthesis cytoplasmic matrix proteins. c) Synthesis of secreted proteins d) Synthesis of lipofuscin pigments. 2- Residual bodies: a) Are the digested material in the secondary lysosome. b) Are the undigested material in the secondary lysosome. c) Are the undigested material in multivesicular bodies. d) Are primary lysosomes. 3- Which of the following is NOT a membranous organelle? a) Lysosomes. b) Filaments. c) Peroxisomes. d) Mitochondria. 4- In the mitochondria: a) The outer membrane projects inside to form cristae. b) The inner membrane projects inside to form cristae. c) The surface of the outer membrane is much greater than that of the inner membrane. d) No space between inner and outer membranes. 5- All the statements concerning SER are true EXCEPT: a) Found in lipid synthesizing cells. b) Responsible for detoxification of toxins and drugs. c) It contains ribosomes on its surface. d) In the muscle, it is called sarcoplasmic reticulum 6- Golgi have the following functions EXCEPT: a) Synthesis of proteins. b) Packing of proteins. c) Condensation of proteins. d) Modification of proteins. 20 Pr. Sayed Anwar Sayed Hasan Lecture (8) BONES AND CARTILAGE Learning objectives: After this lecture, student should be able to: -Know the structure of bone. -Describe the different of types of bones. -Know the growth and ossification of bones.. -Identify the bone marrow and periosteum. -Identify the different types of cartilage in the body. -Understand the role of bones in support and locomotion. -Understand the definition and types of bone fractures. The example (s) for long bones is (are) A. Humerus. B. Femur. C. Clavicle. D. A &B. E. A, B & C. FUNCTIONS OF BONES The human skeleton serves the following functions: (a) Bodily Support: The skeletal system provides a framework for the human body. (b) Protection: The skeleton protects certain soft structures within the human body. An example is the skull, which surrounds the brain and the thoracic cage which protect the heart and lungs. (c) Motion: Muscles are attached to and move the bones. Bones provide leverage for motion. (d) Formation of Blood Cells (Hematopoiesis): Blood cells are manufactured in the red bone marrow, mainly found in flat bones. (e) Storage for salts (e.g., calcium). TYPES OF BONES according to its shape a. Long Bones: Each bone has two ends and a shaft. Example: femur, clavicle and humerus. b. Short Bones: The short bones, such as those of the wrist and feet, have a thin layer of compact bone surrounding an inner mass of spongy bone. Example: carpal and tarsal bones. 1 Pr. Sayed Anwar Sayed Hasan Types of bones c. Flat Bones: The flat bones are constructed with two plates of compact bone which enclose between them a layer of spongy bone. The spongy bone is richly supplied with blood vessels and red marrow. Example: the scapula and the cranial bones. d. Irregular Bones: The irregular bones are those that do not fit into the three categories above. Example: a vertebra. e. Pneumatic Bones: it has multiple air filled spaces Example: para nasal sinuses. f. Small long Bones: it has single.epiphyses Example: metacarpal and metatarsal bones. g. Sesamoid Bones: Sesamoid bones are small masses of bone that develop in tendons at points where great forces are applied to the tendons. The most obvious and largest sesamoid bone is the patella, or kneecap. 2 Pr. Sayed Anwar Sayed Hasan Types of bones Pneumatic bones Another classification of bones based on the structure of the bones: (a) Compact bone is dense, forms the tubular bodies of long bones and filled with yellow bone marrow; (b) Cancellous (spongy) bone is lattice of bone spicules. It occurs in the ends of long bones and fills the flat and irregular bones.The spaces between the spicules are filled with red bone marrow. 3 Pr. Sayed Anwar Sayed Hasan Structure of long bone BASIC STRUCTURE OF AN INDIVIDUAL BONE (1) Cortex: The cortex is the outer layer of the individua1 bone. It compact (dense) bony tissue. (2) Medulla: The medulla is the central portion of the individual bone. It generally consists of cancellous (spongy) bone tissue. In some bones, particularly long bones, the medulla may include a space without any bony tissue. This space is called the medullary or marrow cavity. (3) Marrow: Marrow serves as a filler of the inside of bones. There are two types of bone marrow--yellow bone marrow and red bone marrow: Yellow bone marrow is mostly yellow fat tissue. Red bone marrow is the only site in adults for the formation of red blood cells (hematopoiesis). 4 Pr. Sayed Anwar Sayed Hasan (4) Periosteum: The periosteum is a covering of the bone surface area not covered by articular cartilage. The periosteum is well supplied with blood vessels and sensory-type nervous tissue. Named Parts of an Individual Long Bone Shaft (diaphysis): The shaft is the central portion of a long bone. Here, the cortex is thickened as required by applied physical stresses. Ends (epiphyses):The ends of long bones are made up mainly of cancellous (spongy) bone tissue. An articular cartilage covers each area where a bone contacts another bone(s). This articular cartilage is made up of hyaline cartilage tissue and provides a smooth surface for motions. Ossification Centers An ossification center is a growing mass of actual bone within the preformed material. (1) Initial bone formation involves destruction of the preforming material and replacement with bony tissue. (2) In the development of long bones, there are two types of ossification centers: (a) Diaphyseal--in the shaft region. (b) Epiphyseal--in the end(s) 5 Pr. Sayed Anwar Sayed Hasan Blood Supply of an Individual Bone A system of blood vessels enters and spreads out through the periosteum. Additional blood vessels, called "nutrient vessels," penetrate the cortex' of the bone and spread out through the marrow. The passageways for penetration of these vessels are called the nutrient canals. 6 Pr. Sayed Anwar Sayed Hasan DEVELOPMENT OF AN INDIVIDUAL BONE The human skeleton is "preformed" early in the fetus, but the early form is not of bony material. There are two types of bones according to their preformed basis: membranous bones and cartilage bones. 1) Membranous bones: The outer skull bones and the clavicle are an example of membranous bones. Osteoblasts invade a membrane to form a center of ossification (formation of bone). Bone-forming activity spreads out from this center until a full bone plate is formed. (2) Cartilage bones: In the fetus, many bones, for example, long bones exist first as models formed of cartilage. Cartilage models of the bones form from mesenchyme during the fetal period, and bone subsequently replaces most of the cartilage. Membranous ossification Cartilaginous ossification 7 Pr. Sayed Anwar Sayed Hasan A brief description of endochondral ossification helps to know how long bones grow: The mesenchymal cells condense and differentiate into chondroblasts, (dividing cells in growing cartilage tissue) thereby forming a cartilage bone model. In the midregion of the model, the cartilage calcifies with calcium salts), and periosteal capillaries (capillaries form the fibrous sheath surrounding the model) grow into the calcified cartilage of the bone model and supply its interior. These blood vessels, together with associated osteogenic (bone-forming) cells, form a periosteal bud. The capillaries initiate the primary ossification centre, so named because the bone tissue it forms replaces most of the cartilage in the main body of the bone model. The shaft of a bone ossified from the primary ossification center grows as the bone develops. ♦Most secondary ossification centers appear in other parts of the developing bone after birth; the parts of a bone ossified from these centers are epiphyses. The chondrocytes in the middle of the epiphysis hypertrophy, and the bone matrix (extracellular substance) between them calcifies. Epiphysial arteries grow into the developing cavities with associated osteogenic cells. 8 Pr. Sayed Anwar Sayed Hasan ♦ The flared part of the diaphysis nearest the epiphysis is the metaphysis. For growth to continue, the bone formed from the primary center in the diaphysis does not fuse with that formed from the secondary centers in the epiphyses until the bone reaches its adult size. Thus, during growth of a long bone, cartilaginous epiphysial plates intervene between the diaphysis and epiphyses. These growth plates are eventually replaced by bone at each of its two sides, diaphysial and epiphysial. When this occurs, bone growth ceases, and the diaphysis fuses with the epiphyses. Longitudinal growth in a growing long bone is liable to be interrupted prematurely, if a fracture passes through which of the following? a-Metaphysis b-Diaphysis c-Epiphyseal plate. d-Epiphyseal line 9 Pr. Sayed Anwar Sayed Hasan THE HUMAN SKELETON a. The human skeleton is a collection of individual bones articulated (joined) together. b. The major subdivisions of the skeleton are the axial skeleton and the appendicular skeleton. THE AXIAL SKELETON The axial skeleton is the central framework of the human body. It includes the skull, the hyoid bone, the vertebral column (spine), and the thoracic cage ( chest or rib cage). a. Vertebral Column (Spine): The vertebral column, or spine, is made up of a vertical series of bony blocks called vertebrae. These vertebrae are joined together in such a way as to form a semiflexible rod. The spine is the central support for the trunk, yet allows trunk movements. (1) Anatomically and functionally, a typical vertebra major parts: (a) The vertebral body is a drum-shaped cylindrical inferior surfaces are flat. Its function is primarily weight-bearing. (b) The neural arch extends posteriorly, arching over and protecting the spinal cord of the central nervous system. From the neural arch are several processes. These processes serve as attachment areas for the trunk muscles. They also act as levers during various trunk motions. Parts of the vertebra (2) The vertebral column has 32-33 vertebrae, one on top of the other. These vertebrae are arranged in regions. The vertebrae of each region have a characteristic shape. The regions are as follows: 10 Pr. Sayed Anwar Sayed Hasan (a) Cervical (neck) region, with seven cervical vertebrae. (b) Thoracic (chest) region, with twelve thoracic vertebrae. (c) Lumbar (low back) region with five lumbar vertebrae. (d) The sacrum, which is a bony fusion of five sacral vertebrae. (e) The coccyx ,with 3-4 coccygeal vertebrae together. (3) The vertebrae are held together in two ways: (a) The intervertebral disc holds the bodies of adjacent vertebrae together. The intervertebral disc is a fibrous ring (annulus fibrosus) with a soft center (nucleus pulposus ). This disc allows the vertebral bodies to move on one another. This joint between the vertebral bodies is a secondary cartilaginous joint. (b) The various parts of adjacent vertebrae are held together by ligaments. A ligament is a dense fibrous connective tissue structure which extends from bone to bone. These ligaments extend along the vertebral column from the base of the skull all the way down to the coccyx. b. The Thoracic (Rib) Cage: The rib cage forms a protective enclosure for the vital organs contained within the thorax (chest) such as the heart and lungs. It also allows the movements of breathing to take place. (1) The sternum lies in the midline of the thorax anteriorly. It is made up of three parts: the manubrium at the top, the body as the main part, and the xiphoid process below. The Thoracic cage 11 Pr. Sayed Anwar Sayed Hasan (2) The rib cage consists of the 12 thoracic vertebrae,12 pairs of ribs, and the sternum. Each rib is curved laterally from back to front. All 12 pairs of ribs are attached posteriorly' to the thoracic vertebrae. The upper seven pairs of ribs are attached directly to the sternum by their costal cartilages (by attaching to the costal cartilage of the rib above). Rib pairs 11and 12 do not attach to the sternum. Instead, they are embedded in the trunk wall muscles. c. The Skull: The skull is the bony framework (skeleton) of the head region. It has two major subdivisions: the cranium which encases and protects the brain and the facial skeleton which is involved with the beginnings of the digestive and respiratory systems. The special sense organs (eyes, ears, etc.) are included and protected within the skull. (1) The bones of the cranium form a spherical case around the brain. With age, the sutures between the cranial bones become more solid. The cranium has a base with several openings for the passage of blood vessels and nerves. The vault (or calvaria) is made up of flat bones arching over and covering the brain (2) The facial skeleton consists of bones which surround the nose and the mouth. These are mainly flat and irregular bones. The skull Bones of the facial skeleton also form part of the orbit of each eye. (3) The upper jaw (maxilla) and the lower jaw (mandible) are parts of the facial skeleton which surround the mouth. (5) The hyoid bone is located at the junction between the head and the neck. It is not articulated directly with the other bones. It is held in place and moved around by groups of muscles above and below. THE APPENDICULAR SKELETON a. The appendicular skeleton is made up of the skeletal elements of the upper and lower limbs (often referred to as the "extremities"). These limbs are appended (attached) to the axial skeleton. CARTILAGE A type of connective tissue in which the cells and fibers are embedded in gel like matrix, covered by fiberous membrane called perichondrium. There are three types of cartilage: 12 Pr. Sayed Anwar Sayed Hasan -Hyaline cartilage: in epiphyseal plate, articular cartilage, foetal bones, costal cartilage It is 2nd most flexible cartilage. - White fibrocartilage: in intra-articular disc, intervertebral disc, symphysis pubis. It is the least flexible. -Yellow elastic cartilage: in ear auricle, auditory tube, epiglottis, external auditory meatus. It is most flexible cartilage Hyaline cartilage Fibrocartilage Elastic cartilage 13 Pr. Sayed Anwar Sayed Hasan Lecture (9) JOINTS Learning objectives: After this lecture, student should be able to: - Know the definition and structure of the joints. - Know the different divisions of the joints. - Describe the fibrous joints. - Describe the cartilaginous joints. - Describe the synovial joints and its stability. - Understand the role of the joints in body movements. - Understand the definition and types of joint dislocations. Definition: A joint, or articulation, is the location where two or more bones meet Classification Joints are classified according to the kind of material holding the bones together and the relative freedom and kind of motion at the particular joint into the following types: (a) Fibrous Joints. (b) Cartilagenous Joints (c) Synovial Joints. I- Fibrous Joints Here the bones are connected together by a fibrous tissue. Varying degrees of motion, from none to some, are possible in fibrous joints. Subtypes of fibrous joints 1) Syndesmosis: When the bones are held together by fibrous connective tissue, the joint is referred to as a syndesmosis. SYN=together DESMOS=fiber (a typing material) Examples: The inferior tibio-fibular joint, the interosseous membrane connecting between the radius and ulna in the upper limb and tibia and fibula in the lower limb. 2)Sutures: When the bones are quite close together with a minimum of fibrous connective tissue, the joint is known as a suture. Example: the joints between the cranial bones (bones of the vault of the skull). 3) Gomphosis: it’s the joint connecting the root of the tooth to its socket All are fibrous joints except: A. Synchondrosis. B. Gomphosis. C. Sutures. D. Syndysmosis. 1  Pr. Sayed Anwar Sayed Hasan Syndesmosis Fibrous joint (coronal suture of skull) II- Cartilaginous Joints Here the bones are bounded together by intervening cartilage and permit a limited degree of movement. They are of two types: (1) Primary (Synchondrosis) A cartilaginous joint in which the bones are held together by a hyaline cartilage. SYN = together CHONDRO = cartilage Example: Epiphyseal plate in long Primary cartilaginous Joints growing bones (synchondrosis). 2  Pr. Sayed Anwar Sayed Hasan 2)Secondary cartilaginous joint (Symphysis) A joint in which the bones are held together by a fibrocartilage and the articular surfaces of the bones are covered by a thin layer of hyaline cartilage Examples: Pubic symphysis, the inter vertebral disc between bodies of vertebrae (symphyses) and manubriosternal joint (between the sternal body and the manubrium). Secondary cartilaginous Joints III Synovial Joints In the synovial type of joints, the bones move on one another so as to allow various motions of the body parts. The "ovial" part of the name refers to the fact that the fluid substance seen in this type of joint appeared to the old anatomists to be like raw egg white (ovum = egg). THE TYPICAL SYNOVIAL JOINT The "typical" synovial joint has the following parts: Structure of the synovial joint 1- Bony articular ends, which are usually large and smooth. 2- Articular cartilages: The "contact" points of the bones are usually covered with a layer of lubricated hyaline cartilage. Where these cartilages end, the synovial membranes begin. Cartilages provide a smooth surface to reduce friction. Synovial Joint 3 Pr. Sayed Anwar Sayed Hasan 3. Synovial Membrane, Space, and Fluid: (1) Synovial membrane: The synovial membrane lines the inner surface of the capsule. It secretes synovial fluid into the synovial space. (2) Synovial space: The space within the capsule allows movement. (3) Synovial fluid: Synovial fluid is a colorless, viscous fluid similar in consistency to raw egg white. It lubricates the articulation. 4. Capsule: The "typical" synovial articulation is surrounded by a sleeve of dense fibrous connective tissue known as the capsule. The capsule encloses the articulation. 5. Ligaments: Primarily, ligaments hold bones together. Ligaments also may help restrain motion in certain directions and stabilize the articulation. 6. Muscles. Skeletal muscles apply the forces to produce given motion Classification of Synovial Joints Is based on shapes of articular surfaces of bones or on types of movement I. According to the axis of movement 1.Uniaxial Synovial Joints allows movement in one plane Examples: (a) Plane joints. (b) Hinge joints. (c) Pivot joint. 2. Bi-Axial Synovial Joints allows movements in two planes Examples: (a) Condyloid joints. (b)Ellipsoid joint. (c) Saddle joint. 3. Multi-axial Synovial Joints allows movements in multiple planes Example Ball and socket joint. 4 Pr. Sayed Anwar Sayed Hasan II- According to the shape of articular surfaces Uniaxial Synovial Joints (1)Plane joints: the two articular surfaces are flat and permit only slight gliding movement. Example: intercarpal and intertarsal joints and Sternoclavicular, acromioclavicular joints (2)Hinge joints: configuration of bones allow movement on one axis. Example: interphalangeal joints (Fingers), elbow Plane synovial joints joint and ankle joint. (3)Pivot joint: where one bone act as an axis and the another form a circle around this axis. In this joint either the circle rotates around the axis as the proximal radioulnar joint or the axis rotates inside the circle as the median atlantoaxial joint. Hinge synovial joint Pivot synovial joints 5 Pr. Sayed Anwar Sayed Hasan Bi-Axial Synovial Joints In bi-axial synovial joints, motion between the bones occurs in two planes. Here the surface in contact is curved or rounded in two directions. (4) Condyloid joints: The proximal phalanx of a finger can flex and extend and move from side to side on the rounded head of the metacarpal bone. This is the metacarpophalangeal joint. (5) Ellipsoid joint: Elliptical convex Condyloid synovial joint surface of carpal bones articulates with elliptical concave surface of radius in the wrist joint (Radiocarpal). (6) Saddle joint: one of the articular surfaces is partly convex and partly concave and the other surface are reciprocally concave convex. eg. Carpometacarpal joint of the thumb. Ellipsoid synovial joint Saddle synovial joint 6 Pr. Sayed Anwar Sayed Hasan Multi-Axial Synovial Joints In multi-axial joints, motion is possible in all three planes of space. The ball-and-socket-type synovial joint A spherically rounded head (ball-like) fits into a receiving concavity (socket). The hip joint is an example of the ball-and-socket type, with the spherical head of the femur fitting into the cup or socket (acetabulum) of the pelvic bone Ball and socket synovial joint Stability of joints Any joint is stabilized by the following factors: 1 -Bony factor (the shape of articulating surfaces) example: in the hip joint the head of the femur is well adapted in the acetabulum. 2-Ligamentous factor: the strength of the fibrous capsule and the surrounding ligaments play a very important role in stability of joints as they prevent over movement and guard against sudden accidental stress. 3-Muscular factor: strong muscles surrounding a joint stabilize it. 4-Intra-articlar pressure. 7 Pr. Sayed Anwar Sayed Hasan Factors which limit the movements of a joint 1- Tension in the ligaments. This is apparent in attempting extension of the knee. 2- Contraction of the antagonistic muscles. In flexion of the hip while the knee is extended, flexion of the hip is limited. In flexion of the hip while the knee is flexed, the hamstring muscles are relaxed allowing more extension of the hip. 3- Increased compression between opposing articular surfaces. 4- Approximation of soft tissues. Flexion of the elbow is limited by contact of the forearm to the arm. Choose the correct answer: 1-In…………joint there is a central bony pivot surrounded by a bony-ligamentous ring. A) Pivot. B) Saddle c) Hing. D) Ball & socket 2-………Joints have two distinct convex surfaces that articulate with two concave surfaces. A) Hing. B) Ball & socket C) Ellipsoid. D) Condyloid 8  Faculty of Medicine Histology Department NON-MEMBRANOUS ORGANELLES Lecture 10 In Block 102PMS Dr/ Maha Mahmoud Abd El Rouf Lecturer of Histology Histology and cell biology Department/ Faculty of Medicine/Assiut University 2023- 2024 Learning objectives After the lecture, students should be able to: - Define cytoskeleton and enumerate its components. - Discriminate the structure and function of microtubules and centrosomes. - Illustrate the structure and function of microfilaments. - Recognize structure and types of intermediate filaments. - Describe the structure and types of ribosomes. 1  Non- Membranous organelles They include: 1- Cytoskeleton which includes (Microfilaments, Intermediate filaments and Microtubules) 2- Proteosomes 3- Centrosomes 4- Ribosomes The Cytoskeleton The term cytoskeleton collectively refers to three separate classes of proteins seen as fine cytoplasmic filaments. Microfilaments (also called actin filaments); have the smallest diameter ; about 6 nm. Intermediate filaments; they are about 8 to 10 nm in diameter. Microtubules, which are about 25 nm in diameter. Function: 1-Determine the shapes of cells. 2- Play an important role in the movements of organelles and cytoplasmic vesicles. 3- Allow the movement of entire cells. Cytoskeleton 2  1-Microtubules Microtubules are fine tubular structures within the cytoplasm of all eukaryotic cells. Structure: - Each microtubule is hollow, a rigid structure with an outer diameter of 25 nm, that help to maintain cell shape. - The protein subunit of a microtubule is a heterodimer of α and β tubulin. - The tubulin subunits align as protofilaments. - The circumference of each microtubule wall is formed of 13 protofilaments. - Microtubule are highly dynamic in length by a process of polymeraization or depolymerization of tubulin subunits. Functions: 1-Microtubules maintain the cell shape. 2- Help in intracellular transport of membranous vesicles, macromolecules and organelles. 3- Microtubules are organized to form dynamic structures such as mitotic spindle of cell division, centrioles, basal bodies and axoneme of cilia and flagella. Mitotic spindle cilia and basal body 3  Microtubular transport Change of microtubule length -------------------------------------------------------------------------------------------------------- 2-Microfilaments (Actin Filaments) - Actin filaments are thin (6 nm diameter), shorter and more flexible than microtubules. - The cytoplasmic actin filament is a thin 6-nm wide, very long polymer of a globular actin monomer; it is a homopolymer in that all its protein subunits are the same. - The actin filaments in a cell are highly dynamic (they are in a constant state of assembly and disassembly). 4  Functions: 1- Actin filaments are found in great abundance in muscle cells (they make up about 60% of the protein in these cells); actin filaments integrated with myosin (a motor protein) permit very forceful contractions. 2- They are found as a major protein (10% to 15%) in essentially all non muscle cells as well, where they play a central role in "cell locomotion", "maintenance of cell shape", "translocation of cell organelles", "formation of the contractile ring in mitosis", and numerous other activities. -------------------------------------------------------------------------------------------------------- 3-Intermediate Filaments - They are intermediate in size between the other two components, with a diameter averaging 10 nm. - Unlike microtubules and actin filaments, these intermediate filaments are stable. - Intermediate filament proteins have particular biological, histological, or pathological importance. - They are made up of different protein subunits in different cell types. - Intermediate filaments can be localized in various cells by immunohistochemistry. There are 6 major classes of intermediate filaments Intermediate filament protein Cell distribution Acidic cytokeratin Epithelial cells Basic cytokeratin Epithelial cells Vimentin Mesenchymal cells desmin Muscle cells GFAP Astrocytes Neurofilaments ( NF) Neurons Lamins Nuclei of all cells Nestin Neural stem cells 5  Keratins or cytokeratins: in all epithelial cells. Intermediate filaments of keratins form large bundles (tonofibrils) that attach to certain junctions between epithelial cells. In skin epidermal cells, cytokeratins accumulate during differentiation in the process of keratinization producing an outer layer of non-living cells.  Vimentin: is found in most cells derived from embryonic mesenchyme.  Important vimentin-like proteins include desmin found in almost all muscle cells and glial fibrillary acidic protein (GFAP) found especially in astrocytes (supporting cells of central nervous system tissue).  Neurofilament proteins are the major intermediate filaments of neurons.  Lamins are the intermediate filaments form the nuclear lamina associated with the inner membrane of the nuclear envelope. Lamins help maintain nuclear shape, participate in anchoring chromatin to the nuclear envelope and participate in nuclear assembly-disassembly during cell division. 6  CYTOSKELETON Ribosomes Ribosomes: are small, non- membranous organelles about 20 × 30 nm in size, present in all animal cells in varying amounts depending on their activity in protein synthesis. Structure: A functional ribosome has two subunits (small subunit& large subunit) bound to a strand of mRNA. Chemically; ribosomes are composed of ribosomal RNA (rRNA) and proteins. 7  - These ribosomal proteins are themselves synthesized in cytoplasmic ribosomes, but are then imported to the nucleus where they associate with newly synthesized rRNA. The ribosomal subunits thus formed then move from the nucleus to the cytoplasm where they are reused many times, for translation of any mRNA strand. - During protein synthesis many ribosomes typically bind the same strand of mRNA to form larger complexes called polyribosomes, or polysomes. - In stained preparations of cells polyribosomes are intensely basophilic because of the numerous phosphate groups of the constituent RNA molecules. Types of polyribosomes: 1- Free polyribosomes: They exist as isolated cytoplasmic clusters and synthesize cytoplasmic proteins needed for cellular growth and differentiation. 2- Bound polyribosomes:  Endoplasmic reticulum (ER) Bound polyribosomes: Polyribosomes attached to membranes of the endoplasmic reticulum (RER). They are involved in the formation of membrane proteins of the ER, the Golgi apparatus, or the cell membrane; enzymes to be stored in lysosomes; and secretory proteins.  Polyribosomes associated with the outer membrane of the nuclear envelope. The outer membrane itself is continuous with the (RER). 8  Proteasomes - Proteasomes are very small abundant protein complexes not associated with membrane, each approximately the size of the small ribosomal subunit. - Whereas lysosomes digest organelles or membranes by autophagy; proteasomes deal primarily with free proteins molecules including denatured and short-lived proteins. - Centrosomes Structure: - It is composed of two cylindrical centrioles surrounded by a pericentriolar matrix (PCM) that found close to the nucleus of dividing cells. - The two cylindrical centrioles have their long axes at right angles. - Each centriole is composed of nine highly organized microtubule triplets and there are no central microtubules. Before cell division, more specifically during the period of DNA replication, the centrosome duplicates itself so that now each centrosome has two pairs of centrioles. 9 Functions: 1-During mitosis, the centrosome divides into halves, which move to opposite poles of the cell, and become organizing centers for the microtubules of the mitotic spindle. Cells lack centrosomes cannot divide. 2- It serves as the basal body for cilia. Ciliated cells contain hundreds or even thousands of basal bodies or centrioles. 3- It serves as the basal body from which the microtubules of the tail of the sperm grow. References  Lippincott Illustrated Reviews: Integrated systems. 2016; 2: 41–42.  Elsevier’s Integrated Histology. 2007; 1: 24- 30.  Junqueira’s Basic Histology Text & Atlas. 2018; 1: 37 and 42- 47. 11  Self Assessment 1- Which structure is directly responsible for the formation of proteins within the cell? a) Lysosomes b) Vacuoles c) Centrioles d) Ribosomes e) SER 2- Regarding centrioles all of the following are correct EXCEPT: a) Occur in pairs. b) Duplicate prior to mitosis. c) Located near the nucleus. d) Comprised of microfilaments. e) Function in the formation of mitotic spindle. 3- All of the following structures are made from microtubules except: a) Cilia b) Flagella c) centrosome d) Mitotic spindle e) Microvilli 4- Regarding microfilaments, which is incorrect ? a) They are one of the components of the cytoskeleton. b) Their wall is composed of a protein called desmin. c) Their wall is composed of a protein called actin. d) They are very thin structures about 5 nm in diameter e) They form of the contractile ring in mitosis 5- The intermediate filament ……….. is found in all nuclei, but …………… is the intermediate filament characteristic for astrocytes. 6- The ………… is composed of nine highly organized microtubule triplets and there are no central microtubules. 7- Enumerate 2 important intermediate filaments. 11