Introduction to Anatomy and Physiology

Republic of the Philippines KOLEHIYO NG LUNGSOD NG DASMARIÑAS City of Dasmariñas INSTITUTE OF NURSING INTRODUCTION TO ANATOMY AND PHYSIOLOGY Anatomy - derived from the Greek terms Ana (“up) and tome (“cutting”) w...

Republic of the Philippines KOLEHIYO NG LUNGSOD NG DASMARIÑAS City of Dasmariñas INSTITUTE OF NURSING INTRODUCTION TO ANATOMY AND PHYSIOLOGY Anatomy - derived from the Greek terms Ana (“up) and tome (“cutting”) which literally means “cutting up” - means to dissect, or cut apart and separate, the parts of the body for study - the study of internal and external structure and the physical relationships between body parts - includes a wide range of study: how structures develop, their microscopic organization, the relationship of one structure to another and how structures and functions are interrelated Subdivisions of Anatomy 1. Gross (macroscopic) Anatomy – Study of the large structures of the human body that can be seen through normal dissection 2. Microscopic Anatomy – Study of the smaller structures and fine details that can be seen with the aid of a microscope – Subdivided into specialties: a. Histology – study of tissues b. Cytology – study of cells 3. Embryology – Study of structures that emerge from the time of the fertilized egg through the eight week in utero 4. Comparative Anatomy – Comparison of anatomic structures both gross and microscopic in different animals 5. Surface Anatomy (Superficial Anatomy) – A descriptive science dealing with anatomical features that can be studied by sight, without dissecting an organism. – Includes the form and proportion of the human body – Includes also the surface landmarks which correspond to deeper structures hidden from view 6. Systemic Anatomy – Anatomy of the systems of the body – An approach to anatomical study organized by organ systems 7. Regional Anatomy – Study of specific regions of the body, such as the head, neck, or trunk – Emphasizes the specific relationship between different structures in a particular region and is quite useful for gross anatomy studies as well as for surgical anatomy 8. Radiographic Anatomy – Study of the anatomy of tissues or organs based on the visualization from x-ray films 9. Pathological Anatomy – The anatomical study of changes in the structure, or appearance of organs or tissues, including postmortem examinations and the study of biopsy specimens Physiology - study of how the body parts work or function - the science of body functions - it is important in physiology to recognize structures as dynamic rather than static or unchanging - functions are more complex and much more difficult to examine than most anatomical structures 1  - function can never be separated completely from structure, we can understand the human body best by studying anatomy and physiology together Major Goals of Physiology 1. To understand and predict the body’s responses to stimuli 2. To understand how the body maintains conditions within a narrow range of values in the presence of a continually changing environment. Subdivisions of Physiology 1. Neurophysiology – Study of functional properties of nerve cells 2. Endocrinology – Study of hormones and how they control body functions 3. Cardiovascular Physiology – Study of functions of the heart and blood vessels 4. Immunology – Study of how the body defends itself against disease-causing agents 5. Respiratory Physiology – Study of functions of the air passageways and lungs 6. Renal physiology – Study of functions of the kidneys 7. Exercise Physiology – Study of changes in cell and organ functions as a result of muscular activity 8. Pathophysiology – Study of functional changes associated with disease or injury Relationships between Anatomy and Physiology Each body part has a specific job or work to do to make the body work as one unit Structures determine what functions can be performed. Anatomy and Physiology are interrelated because structure influences function and function affects structure. The sciences of anatomy and physiology are the foundation for understanding the structures and functions of the human body. LEVELS OF STRUCTURAL AND FUNCTIONAL ORGANIZATION One of the most outstanding features of the complex human body is its order and organization: how all the parts, from tiny atoms to visible structures work together to make a functioning whole. To understand the human body, we must examine its organization at several different levels. 1. Chemical Level - Involves interaction between atoms (the smallest units of matter that participate in chemical reactions) and their combinations to form molecules. Molecules contribute to the make-up of a cell, which is the basic unit of life. o Examples of molecules found in the body (needed for a variety of chemical processes): a. deoxyribonucleic acid (DNA) – genetic material passed from one generation to the next b. glucose – commonly known as blood sugar c. hemoglobin d. water, fats, proteins, and vitamins - There are about 90 naturally occurring elements and another 16 that are man-made in the laboratory. Only 20 are needed by living organisms. - Four (4) elements (C, H, O, N) make up 95% of the human body by weight. - Structural and functional characteristics of all organisms are determined by their chemical makeup - Molecules combine to form structures at the next level of organization 2. Cellular Level - Cells are the basic structural and functional units of all organisms; estimates indicate that there are about 100 trillion dynamic cells in the human body; 2  cells vary in size, shape and structure, reflecting their particular functions in the body. - Cells makeup this level of organization and the smallest living units in the human body - Types of body cells – muscle cells, nerve cells, and blood cells - Cells contain specialized structures called organelles (nucleus, mitochondria, lysosome and etc.) 3. Tissue Level - A group of cells with similar structure and function plus the extracellular substances located between them make up a tissue. - The characteristics of the cells and the surrounding materials determine the functions of the tissue. - There are four basic types of tissue in the body: epithelial, connective, muscle and nervous. 4. Organ Level - An organ is composed of two or more different types of tissues with a common function. - Examples: stomach, heart, liver, and lungs 5. Organ System Level - An organ system is a group of organs that work together to perform a specific function Ex. Nervous, digestive and respiratory system 6. Organismal / Organismic / organism Level - Highest and largest level of organization and most complex which is made up of several systems that work together to maintain life. - All the systems of the body combine to make up an organism, that is, one human being. ***The organization at each level determines both the structural characteristics and the functions of the higher levels. ORGAN SYSTEMS OVERVIEW 1. Integumentary System - consists of the skin and accessory organs (hair, nails, sweat and sebaceous glands) - Functions: > covers, cushions and protects underlying tissues from injury > protects against water loss > perceives stimuli through sense receptors > helps in temperature regulation > synthesize chemicals (e.g. vitamin D precursors) 2. Skeletal System - includes bones, cartilages, ligaments, joints - Functions: > provides the body’s framework > provides support and protection > provides attachment for muscles and ligaments thereby allowing body movement > produces blood cells and stores minerals 3. Muscular System - consists of muscles - Functions: > produces body movements and maintains posture > produces body heat 4. Nervous System - consists of the brain, spinal cord, nerves and sensory receptors - Functions: > major regulatory system: detects sensation > controls movement > control physiologic and intellectual functions > coordinates body activities 3  > receives and transmits stimuli 5. Endocrine System - consists of endocrine glands and their hormones - Functions: > major regulatory system, participates in the regulation of metabolism, reproduction and other body functions 6. Cardiovascular System - includes the heart, blood and blood vessels - Functions: > transports nutrients, waste products, gases and hormones throughout the body > plays a role in the immune response and regulation of body temperature 7. Lymphatic System - includes the lymph vessels, lymph nodes and lymph - Functions: > removes foreign substances from the blood and lymph > combats diseases > maintains tissue fluid balance > absorbs and transports fatty acids and fats to the circulatory system 8. Respiratory System - includes the lungs and respiratory passages - Functions: > exchanges gases between the blood and the air > helps regulate blood pH 9. Digestive System - includes the mouth, esophagus, stomach, intestines, liver and pancreas - Functions: > mechanical and chemical digestion > absorption of nutrients > elimination of waste 10. Urinary System - includes the kidneys, urinary bladder, ureters and urethra -Functions: > removes waste products from the circulatory system > helps regulate blood pH, ion balance and water balance 11. Reproductive System - includes gonads, accessory structures and genitals of male and female -Functions: > performs the processes of reproduction > controls sexual functions and behaviors BASIC LIFE PROCESSES All living organisms have certain characteristics that set them apart from nonliving things. 1. Organization o A condition in which parts of an organism have specific relationships to each other & interact to perform specific functions o Living things are highly organized. o Disruption of this organized state can result in loss of functions and death. 2. Metabolism o All chemical reactions that occur in the body a) Catabolism ▪ Complex substances are broken down into simpler building blocks b) Anabolism ▪ Complex substances are synthesized from simpler ones 4  Example: Proteins in food are split into amino acids, which are the building blocks of proteins. These amino acids can be used to build new proteins that make up muscles and bones. 3. Responsiveness o Body’s ability to detect and respond to changes in its internal and/external environment. o Different cells in the body detect different sorts of changes. Nerve cells respond to changes in the environment by generating nerve impulses. Muscle cells respond to nerve impulses by contracting, which generates force to move body parts. 4. Movement o Includes motion of the whole body, individual organs, single cells, and even tiny organelles inside cells. o Examples: - Coordinated action of several muscles and bones enables you to move your body from one place to another by walking or running - when a body tissue is damaged or infected, certain white blood cells move from the blood into the affected tissue to help clean up and repair the area - Inside individual cells, various parts move from one position to another to carry out their functions 5. Reproduction o Formation of new cells for tissue growth, repair or replacement; production of a new individual 6. Growth o Results in an increase in body size due to an increase in the size of existing cells, the number of cells, or the amount of material surrounding cells 7. Differentiation o Developmental process by which non-specialized cells change into specialized cells with distinctive structural and functional characteristics o Examples: - Specialized RBCs and WBCs differentiate from the same unspecialized cells in the bone marrow - Single fertilized egg cell undergoes tremendous differentiation to develop into a unique individual who is similar to, yet quite different from, either of the parents 8. Respiration o The exchange of gases in cells and in the lungs 9. Digestion o Ability to break down food into absorbable pieces for body utilization 10. Excretion o Ability to eliminate waste materials *** Although not all of these processes are occurring in cells throughout the body all of the time, when they cease to occur properly cell death may occur. When cell death is extensive and leads to organ failure, the result is death of the organism. SURVIVAL NEEDS 1. Water - Most abundant substance in the body - About 60% of the adult body weight is attributed to water - Provides a medium in which chemical reactions occur - Transports substances - Helps regulate body temperature 2. Oxygen - Necessary for metabolic reactions that provide energy 3. Nutrients - Supply the chemicals that the body needs for energy, raw materials for making new tissues, for growth, replacement and repair 4. Appropriate body temperature - Extreme changes in body temperature may lead to death 5. Appropriate atmospheric pressure 5  - Force of the air acting on our bodies - Breathing and exchange of oxygen and carbon dioxide in the lungs depend on appropriate atmospheric pressure HOMEOSTASIS o The existence and maintenance of a relatively constant/stable environment within the body o The dynamic state of equilibrium - it can change over a narrow range that is compatible with maintaining cellular life processes. Example: Blood glucose is maintained w/in narrow range and normally does not fall too low between meals or rise too high even after eating a high-glucose meal. o To survive, every living organism must maintain homeostasis o Ensures that the body’s internal environment remains steady despite changes inside and outside the body o Keeps the interstitial fluid (large part of the internal envi.) at a proper temperature of 37 C and maintains adequate nutrient and oxygen levels for body cells to flourish. Homeostasis (homeo = sameness; stasis = standing still) is the condition of equilibrium in the body’s internal environment. Homeostasis in the human body is continually being disturbed. Some disruptions come from the external environment in the form of physical insults such as intense heat or lack of oxygen. Other disruptions originate in the internal environment (within the body), such as blood glucose level that is too low. Control of Homeostasis Every body structure, from cells to systems, has one or more homeostatic devices that work to keep the internal environment within normal limits The homeostatic mechanisms of the body are mainly under the control of: a. Nervous system – detects changes from the balanced state and sends messages in the form of nerve impulses to organs that can counteract the change. Example: when the body temperature rises, nerve impulses cause sweat glands to release more sweat, which cools the body as it evaporates b. Endocrine system – corrects changes by secreting molecules called hormones into the blood. Hormones affect specific body cells where they cause responses that restore homeostasis. Example: Insulin reduces blood glucose level when it is too high *** Nerve impulses typically cause rapid corrections; whereas hormones usually work more slowly. Homeostasis is maintained by means of many feedback systems Feedback Systems - a cycle of events in which a condition in the body is continually monitored, evaluated, changed, re-monitored, reevaluated, and so on. Each monitored variable, such as body temperature, blood pressure or blood glucose level, is termed a controlled condition. Any disruption that causes a change in a controlled condition is called a stimulus. Some stimuli come from the external environment (intense heat or lack of oxygen). - Others originate in the internal environment, such as a blood glucose level that is too low. Homeostatic imbalances may also occur due to psychological stresses in our social environment (demands of work and school). In most cases, the disruption of homeostasis is mild and temporary, and the responses of body cells quickly restore balance in the internal environment. In other cases, the disruption of homeostasis is intense and prolonged, as in poisoning, overexposure to temperature extremes, severe infection, or death of a loved one. - Three basic components that make up a feedback system: 6  o Receptor – body structure that monitors changes in a controlled condition and sends input (nerve impulse or chemical signal) to a control center o Control center – sets the range of values within which a controlled condition should be maintained, evaluates the input it receives from receptors and generates output commands (nerve impulses, hormones or other chemical signals) when they are needed. o Effector – body structure that receives output from the control center and produces a response or effect that changes the controlled condition. Ex. When the body temperature drops sharply, the brain (control center) sends nerve impulses (output) to the skeletal muscles (effectors). The result is shivering, which generates heat and raises body temperature. - Classifications: 1. Negative feedback system – reverses a change in a controlled condition - First, a stimulus disrupts homeostasis by altering the controlled condition. The receptors that are part of the feedback system detect the change and send input to a control center. The control center evaluates the input and, if necessary, issues output commands to an effector. The effector produces a physiological response that is able to return the controlled condition to its normal state. - Most homeostatic mechanisms in the body involve negative feedback - Tends to regulate conditions in the body that are held fairly stable over long periods of time, such as BP, bld. glucose level, and body temperature *** Negative feedback that helps regulate BP- When the heart beats faster or harder, BP increases. The higher the pressure is detected by baroreceptors (pressure sensitive nerve cells located in the walls of certain blood vessels). The baroreceptors send nerve impulses (input) to the brain (control center), which interprets the impulses and responds by sending nerve impulses (output) to the heart (effector). HR decreases, which causes BP to decrease (response). This sequence of events returns the controlled condition, the BP to normal, and homeostasis is restored. This is a negative feedback system because the activity of the effector produces a result, a drop in blood pressure, which reverses the effect of the stimulus. 2. Positive Feedback System – strengthens or reinforce a change in one of the body’s controlled condition - A stimulus alters a controlled condition, which is monitored by receptors that send input to a control center. The control center provides commands to an effector, but this time the effector produces a physiological response that reinforces the initial change in the controlled condition. - Not homeostatic and are rare in healthy individuals - Implies that, when a deviation from a normal value occurs, the response of the system is to make the deviation even greater - Creates a cycle leading away from homeostasis and in some cases results in death - Involves in the regulation of a potentially dangerous or stressful process that must be completed quickly - tends to reinforce conditions that don’t’ happen very often, such as childbirth, ovulation, and blood clotting - other example: inadequate delivery of blood to cardiac muscle as a result of extreme blood loss Homeostasis and Disease As long as all of the body’s controlled conditions remain within certain narrow limits, body cells function efficiently, homeostasis is maintained, and the body stays healthy. The human body is amazingly effective in maintaining homeostasis. Nevertheless, an infection, an injury, or a genetic abnormality can sometimes have effects so severe that homeostatic mechanisms can’t fully compensate for them. When homeostatic regulation fails, organ 7  systems begin to malfunction, and the individual experiences symptoms of illness or disease. ANATOMICAL TERMINOLOGIES Certain basic terms need to be understood in order to communicate effectively in the health professions. This section deals with some basic terms that relate to the anatomy of the body. They are used to describe directions and regions of the body. BODY POSITIONS When using directions in anatomy and physiology, it is always assumed that the body is in anatomical position – a person is standing erect and facing forward with arms at the sides with palms facing forward and feet are flat on the floor and directed forward. ***When using directions in anatomy and physiology, it is always assumed that the body is in anatomical position. ***The position of the body can affect the description of body parts relative to each other. Prone – body is lying face down Supine – body is lying face up REGIONAL TERMS The body is divided in several major regions that can be identified externally. The principal regions are the head, neck, trunk, upper limbs and lower limbs. Head - Consists of the skull and face Neck - Supports the head and attaches to the trunk Trunk - Consists of the chest, abdomen, and pelvis Upper limb - Consists of the shoulder, armpit, arm, forearm, wrist, and hand Lower limb - Consists of the buttock, thigh, leg, ankle, and foot ***Body Regions and Areas with corresponding anatomical and common names: (for locations, refer to the figure in the book) 8  1. head region 16. iliac 2. thoracic region 17. inguinal 3. abdominal region 18. umbilical 4. upper back region 19. hypogastric 5. lower back region 20. pubic 6. upper extremities 21. volar/palmar 7. lower extremities 22. patellar 8. temporal 23. parietal 9. mastoid 24. occipital 10. mammary 25. cervical 11. axillary 26. deltoid 12. epigastric 27. scapular 13. brachial 28. sacral 14. hypochondriac 29. gluteal 15. lumbar 30. popliteal Anatomical and Common Names Anterior cephalic – head frontal – forehead orbital – eye nasal – nose oral – mouth otic - ear buccal – cheek mental – chin cranial – skull facial – face cervical – neck clavicular – collar bone thoracic – thorax sternal – breastbone pectoral – chest mammary – breast axillary – armpit brachial – arm cubital – elbow antebrachial – forearm abdominal – abdomen umbilical – navel pelvic – pelvis inguinal – groin pubic – genital carpal – wrist manual – hand palmar – palm digital – fingers coxal – hip femoral – thigh patellar – kneecap crural – leg pedal – foot talus – ankle dorsum – top of foot digital - toes Posterior occipital – base of skull nuchal – back of neck scapular – shoulder blade dorsal – back acromial – point of shoulder vertebral – spinal column olecranon – point of elbow lumbar – loin sacral – between hips dorsum – back of hand gluteal – buttock perineal – perineum popliteal – hollow behind knee sural – calf plantar – sole calcaneal - heel DIRECTIONAL TERMS – used to describe the relative position of one part to another 1. right – toward the body’s right side 2. left – toward the body’s left side 3. inferior – a structure below another, away from the head, or lower part of a structure ex. The stomach is inferior to the lungs. 4. superior – a structure above another, toward the head, or the upper part of a structure ex. The heart is superior to the liver. 5. anterior/ventral – nearer to or at the front of the body ex. The sternum is anterior to the heart. 6. posterior/dorsal – nearer to or toward the back of the body ex. The esophagus is posterior to the trachea. 7. proximal – closer to the point of attachment to the body than another structure; nearer to the attachment of a limb to the trunk ex. The humerus is proximal to the radius. 8. distal – farther from the point of attachment to the body than another structure; farther to the attachment of a limb to the trunk ex. The phalanges are distal to the carpals. 9  9. lateral – away/ farther from the midline of the body ex. The lungs are lateral to the heart. 10. intermediate – between two structures ex. The transverse colon is intermediate between the ascending and descending colons. 11. medial – toward the middle or midline of the body or nearer the midline ex. The ulna is medial to the radius. 12. visceral – toward the internal organ 13. parietal – toward the wall, away from internal structures 14. peripheral – away from the head, neck and trunk 15. central – refers to the head, neck and trunk 16. ipsilateral – on the same side of the body as another structure ex. The gallbladder and ascending colon are ipsilateral. 17. contralateral – on the opposite side of the body from another structure ex. The ascending and descending colons are contralateral. 18. superficial – toward or on the surface of the body ex. The ribs are superficial to the lungs 19. deep – away from the surface of the body ex. The ribs are deep to the skin of the chest and back 20. cephalic – closer to the head than another structure, synonymous w/ superior ex. The chin is cephalic to the navel 21. caudal - closer to the tail than another structure, synonymous w/ inferior ex. The navel is caudal to the chin PLANES AND SECTIONS To aid in visualizing the internal structures of the body, it is necessary to make a section or cut. The cut is made through the body or an organ along an imaginary line called plane. Plane – an imaginary flat surfaces that pass through the body parts Planes: 1. Sagittal Plane - runs vertically that divides the body or an organ into right and left sides or portions Midsagittal / Median Plane – a vertical plane that passes through the midline of the body or organ and divides it into equal right and left sides 2. Transverse / Cross-sectional / Horizontal Plane - runs parallel to the surface of the ground and divides the body or organ into superior and inferior parts 3. Frontal or Coronal plane - runs vertically from right to left and divides the body into anterior and posterior parts 4. Oblique plane - passes through the body or an organ at an angle between the transverse plane and either a sagittal or frontal plane Sections: Sectioning the body– a way to look inside and observe body’s structures 1. Sagittal Section - refers to a lengthwise cut that divides the body into right and left portions 2. Midsagittal Section - a cut that passes along the body’s midline and divides the body into left and right halves 3. Transverse / Cross Section – a cut at a right angle to the long axis 4. Oblique Section - a cut is made across the long axis at other than a right angle BODY CAVITIES - spaces within the body that contain the internal organs or viscera that help protect, separate and support internal organs 10  1. Dorsal cavities a. Cranial cavity – formed by cranial bones and contains the brain b. Vertebral/ Spinal cavity – formed by vertebral column and contains the spinal cord 2. Ventral cavities a. thoracic cavity – contains the heart, lungs, esophagus, trachea - surrounded by the rib cage, separated to the abdominopelvic cavity by the diaphragm - divided into right and left parts by the mediastinum (central portion of the thoracic cavity and contains the heart, thymus, esophagus, trachea, and large blood vessels); lungs are located on either side of the mediastinum *pericardial cavity – fluid-filled space that surrounds the heart *pleural cavity – each surrounds a lung b. abdominopelvic cavity *abdominal cavity – bounded by abdominal muscles - contains the stomach, liver, gallbladder, spleen, small intestine, and most of the large intestine, pancreas and kidneys *pelvic cavity – small space enclosed by the bones of the pelvis - contains urinary bladder, part of the large intestine, rectum and internal reproductive organs 3. Other cavities a. orbital cavities – also known as the orbits; house the eyes b. nasal cavity - nose c. buccal cavity – also known as the mouth ABDOMINOPELVIC REGIONS AND QUADRANTS To describe the location of the abdominal and pelvic organs more precisely, the abdominopelvic cavity may be divided into smaller compartments. **Abdomen – subdivided superficially into 4 quadrants or 9 regions 1. Quadrants – formed by two imaginary lines(one vertical and one horizontal) crossing at the umbilicus - useful for describing the location of pain, mass, injuries, and other abnormality, which can help a doctor determine the possible cause - RUQ, RLQ, LLQ, LUQ 2. Regions – formed by 4 lines (2horizontal and 2 vertical): top horizontal line is drawn just inferior to the rib cage across the inferior portion of the stomach, bottom horizontal line is drawn just inferior to the top of the hip bones, two vertical lines are drawn through the midpoints of the clavicles, just medial to the nipples - use more precise regional distinctions to describe the location of internal organs and is more widely used for anatomical studies a. Right hypochondriac – right lobe of the liver, gall bladder, small intestine, ascending colon transverse colon, and right kidney b. Epigastric – parts of the right and left lobes of the liver, large portion of the stomach, pancreas, small intestine, transverse colon, right and left adrenal glands, right and left kidneys, and spleen c. Left hypochondriac – small portion of the stomach, tip of liver, tail of pancreas, small intestine, transverse colon, descending colon, spleen, and left kidney d. Right lumbar – tip of liver, gall bladder, small intestine, ascending colon, and right kidney e. Umbilical – stomach, pancreas, small intestine, transverse colon, right and left kidneys, right and left ureters f. Left lumbar – loops of small intestine, descending colon, and tip of left kidney g. Right iliac/inguinal – cecum, ascending colon, parts of small intestine, appendix, right ovary, and right fallopian tube 11 h. Hypogastric – loops of small intestine, sigmoid colon, rectum, right and left ureters, urinary bladder, uterus, right and left ovaries, right and left fallopian tubes, vas deference, seminal vesicle, and prostate i. Left iliac/inguinal – portions of small intestine, descending colon, sigmoid colon, left ovary, and left fallopian tube 12