Chapter 1 Introduction and Organization

Transcription

1 Chapter 1 Introduction and Organization 1. Anatomy and physiology is the relationship of the structure and function of the human body. a. Architect Louis Henry Sullivan coined the phrase Form follows function. This is true of the human body. The function of a specific organ often dictates what form it will take. b. Anatomy - the study of form i. Anatomy is derived for a Greek word meaning to cut apart (ana - up; tome - to cut) which from the time of ancient Greece has been the method for the study of anatomy. (1) Most of the terms that form the language of anatomy are of Greek or Latin origin. List of common prefixes and suffixes inside from cover.) ii. Study of Anatomy can be divided into many parts (1) Surface anatomy - Study of the form and markings of the surface of the body. (2) Gross (macroscopic anatomy) - study of large structures...that can be examined without using a microscope. (3) Two methods of study.. Systemic (systematic)anatomy- (b) Regional anatomy - (4) Histology - study of tissues (microscopic anatomy) (5) Cytology - study of individual cells (either chemically or microscopically - electron microscopic level) (6) Anatomic imaging -using X-ray, ultrasound, MRI, etc. c. Definition of Physiology i. Study of the function of the body. ii. Major goals of physiology are: (1) To understand and predict the responses of the body to stimuli. (2) Understand how the body maintains conditions within a narrow range of values in the presence of a continually changing environment. -1-

2 iii. Physiology like Anatomy can be broken down into multiple levels or disciplines depending on the structures and systems involved. (1) neurophysiology - function of nerve cells (2) Endocrinology - hormones and how they control body function (3) Cardiovascular physiology (4) Immunology (5) Respiratory physiology etc. (6) Cell physiology - function of individual cells 2. Structural and Functional Organization of the Body a. The body consists of several levels of structural organization. These structural levels include: chemical, organelle, cell, tissue, organ, organ system, organism. i. Chemical organization - ultimately everything that we are can be broken down into specific chemicals. (1) (2) (3) ii. Organelles - are small substructures that when collected together constitute a cell. In chapter 3 of this text we will discuss organelles in greater detail. iii. Cells - Cells are the smallest functional unit of life. All living things, whether plant or animal are composed of cells. (1) (2) iv. Tissues - Tissues are composed of similar types of cells all put together. (1) In addition to cells, tissues are composed of extracellular substances (or substances found outside of the cell) which help to bind the cells together. (2) There are 4 primary types of tissues in the body: Epithelium, (b) Connective, (c) muscular and (d) nervous tissue v. Organs - Organs are structures that are made up of two or more different types of tissues. (1) Organs occur throughout the body and vary in size and function. (2) -2-

3 (3) vi. Organ system - also known as systems - These systems are composed of multiple organs working together to perform a common function. (1) For example. The digestive system is composed of teeth, salivary glands, mouth, esophagus, stomach, small and large intestines as well as liver, pancreas, gallbladder etc. There are many different organ systems in the body. vii. Organism - this obviously refers to the combination of all the organ systems which form the overall organism. b. Organ systems -we will use the systemic method of study rather than a regional approach i. Integumentary system - (1) Form: skin, hair, nails and sweat glands (2) Fxn: external support and protection of the body. ii. Skeletal system - (1) Form: bones, associated cartilage and joints (2) Fxn: internal support and flexible framework for body movement; production of blood cells. iii. Muscular system - (1) Form: muscles attached to skeletal system (2) Fnx: body movement and posture -- production of body heat. iv. Lymphatic system - (1) Form: lymph vessels, nodes and other lymph organs (spleen). (2) Fxn: body immunity, absorption of fats; drainage of tissue fluid. v. Endocrine System (1) Form: glands that secrete hormones ie. Pituitary, thyroid, adrenels, ovaries/testes. (2) secretion of hormones for chemical regulation. vi. Respiratory system (1) Form: lungs, bronchus, larynx, nasal cavity, oral cavity (2) Fxn: gaseous exchange between external environment and blood. vii. Nervous system (1) Form: brain, spinal cord, nerves, sensory receptors (2) Fxn: control and regulation of other systems of body; detect sensation intellectual function. viii. Circulatory system (1) Structure: Heart blood vessels and blood. -3-

4 (2) Fxn: transport of life sustaining materials to body cells; removal of meta bolic wastes from cells ix. Digestive system (1) mouth, esophagus, stomach, intestines, and accessory organs ie. liver, gall bladder. (2) Fxn: breakdown and absorption of food materials x. Urinary System (1) Form: kidney ureter urinary bladder urethra (2) Fxn: remove waste products form blood, regulate water balance, ph and ion balance. xi. Reproductive System (1) Female: Form: ovary, uterus vagina production of female sex cells (ova) (b) site of fertilization, implantation of ovum and development of embryo and fetus. (c) (d) Produces milk for newborn produces hormones that influence sexual function and behavior. (Part of endocrine function) (2) Male: Form: testes, prostate, ducts and penis. production of male sex cells (sperm). (b) transfer of sperm to female reproductive system. (c) produces hormones that influence sexual function and behavior. 3. Useful Terminology and Concepts a. Homeostasis - this refers to a range of operating environments that are optimal for life processes to occur. i. Homestasis - Process whereby an organism maintains a steady state condition where cellular processes can be optimally performed. (1) Eg. body temperature (2) Ma intenance of c onstant internal environment in the face of widely fluctuating external environment. (Discussed in detail later). -4-

5 b. Directional Terms - Since the science of anatomy is a descriptive science, it is important to have a basis or a standard from which to begin describing. i. Anatomical Position (1) Person standing erect, feet forward, arms hanging to side palms of the hands facing forward with thumbs to outside. ii. Directional Terms (Table 1.1) (1) Right -right side of body- Eg. Right ear (2) Left -left side of body (3) Superior - higher or above (4) Inferior - lower or below (5) Anterior - before or in front of (6) Posterior - following or after (7) Cephalic - (rosteral) head - toward the head (closer to the head ) (8) Caudal- tail closer to the tail (often synonymous with inferior) (9) Ventral - belly toward the belly (syn with anterior) (10) Dorsal - back toward the back (syn with posterior) (11) Proximal - nearest closer to the point of attachment to the body (12) Distal - to stand apart distant farther from the point of attachment to the body. (13) Medial- middle toward the midline of the body (14) Lateral - side away from the midline of the body (15) Superficial - toward the surface (16) Deep - away from the surface / internal -5-

6 (17) Prone - to lie or be placed with the anterior surface down (18) Supine - to lie or be placed with the anterior surface up c. Planes i. Sagittal - runs vertically through the body and divides it into right and left portions. (1) Midsagittal- directly through the midline (2) Parasagittal- to one side of the midline ii. Transverse - Horizontal - parallel to the ground and divides into supeior / inferior portions. iii. Frontal - Coronal - runs vertically from right to left iv. Longitudinal section - cut through the long axis of an organ v. Cross section - right angle to the long axis vi. Oblique - cut across the long axis at an angle other than a right angel. d. Body Regions - i. Major body regions include: the head, neck, trunk, upper extremity and lower extremity ii. Head and Neck (1) Head - cephalic region (2) Facial region - eyes (orbital), nose (nasal) and mouth (oral) (3) Cranial - covers the brain (4) Neck - Cervical region iii. Trunk - (1) thoracic region (thorax) - chest Mammary region (surrounds the nipple on the breast) (b) Sternal region (between mammary) (c) Axillary - arm pit region (d) Scapular region - shoulder blades (e) Vertebral region - extends length of back (f) Pectoral region - lateral side of thorax (2) Abdominal region -below thorax to pelvis Quadrants (i) Two imaginary line: one horizontal and one vertical 1) intersect the navel Rt. & lt upper and lower (b) Nine regions by 4 imaginary lines (tic tac toe fig.) -6-

7 rt. Hypochondriac epigastric lt hypogastric rt lumbar umbilical lt lumbar rt iliac hypogastric lt iliac (3) Pelvic region - lower portion of the trunk associated w ith the hip pubic area - covered by pubic hair in mature individuals (b) perineum - area of external sex organs and anal opening located (c) lumbar region - small of the back (d) sacral region - vertebral termination (e) gluteal region - large hip muscles. iv. Upper Extremities (1) Shoulder -acromial region (2) Brachium - upper arm (shoulder to elbow) (3) Antebrachium - forearm (elbow to wrist) Cubital region - elbow. (4) Manus - hand Palmar region - palm (b) Dorsum - back of hand v. Lower Extremities (1) Thigh - hip to knee (upper leg or femoral region) (2) Knee - patellar region (b) popliteal region (3) Leg - knee to ankle (4) Pes - foot plantar surface - sole (b) dorsum - top surface e. Body Cavities and structures - confined spaces within the body that contain organs. i. Dorsal (Posterior)Cavity (1) Cranial Brain (2) Spinal Spine ii. Ventral (Anterior) Cavities (Cavities of the trunk) -7-

8 (1) Can be divided into the Thoracic and the abdominopelvic cavity. Thoracic Cavity- surrounded by the rib cage and separated from the abdominal cavity by the muscular diaphragm. (i) Pleural Cavities 1) Contains: Lungs (ii) Mediastinum divides the cavity into right and left. 1) Contains: Great vessels, esophagus, trachea, nerves (iii) Pericardial Cavity - within the mediastinum. 1) Contains: Heart (b) Abdominopelvic Cavity - bounded by abdominal muscles (two parts). (i) Abdominal (Peritoneal) Cavity - 1) Contains: a) Stomach b) Small Intestine c) Large Intestine d) Liver e) Rectum (ii) Pelvic - 1) small space enclosed by pelvis 2) Not physically separated from the peritoneal cavity 3) contains: a) Bladder b) Reproductive organs f. Body Membranes (Serous Membranes) i. Cover, separate and support the organs of the trunk cavity and line the trunk cavities. (1) Two types: Mucous membranes - secrete thick mucus - (i) line cavities that enter or exit the body (nose) (b) Serous membranes (i) line the thoracic and abdominal cavities (ii) secrete water lubricant (serous fluid) (2) Two general locations: Viseral serous membrane - in contact with the organ. -8-

9 ii. (b) Parietal serous membrane - in contact with (lines) the wall of the cavity (3) Space between membrane filled with a thin lubricating film. Reduces friction between organs Cavities and their membranes: (1) Pleural cavity- surrounds the lung. pleurae (sg. Pleura) - serous membranes associated with the lungs (b) cavity contains pleural fluid. (c) parietal pleura -lines thoracic cavity (d) viseral pleura - attached to the outer surface of lungs (2) Pericardial cavity - surrounds the heart and contains a small amount of fluid. viseral pericardium- outer layer of tissue attached to heart (b) parietal pericardium - surrounds the heart (3) Peritoneal cavity - parietal peritoneum - attaches to abdominal wall (b) visceral peritoneum - attaches to viscera (c) mesentery - fused double layer of parietal peritoneum that connects that parietal peritoneum to the visceral peritoneum. (i) Functions 1) anchors visceral peritoneum (organs) to abdominal wall. 2) provides a passageway for blood vessels and nerves to enter organs. (4) Retroperitoneal (b) behind the peritoneum Organs include the kidneys, adrenal glands, pancreas and urinary bladder. g. Homeos tasis i. Homeostasis is the existence and maintenance of a relatively constant environment within the body. (1) Normal function of each cell depends on maintenance of its fluid environment within a constant. temperature (b) volume. (c) chemical content. (2) There is an ideal normal value for each of these called the set point. The body does not maintain these at an exact precise set point -9-

10 (b) but increases and decreases around the set point. Organ systems help control the internal environment so it remains relatively constant. ii. iii. Negative feedback. (1) Most systems of the body are regulated by negative feedback. brings variable back to set point (2) Three components: Receptor (sensor)- monitors the deviations from set point. (i) tension on a tendon, blood glucose, temp. (b) control (integrating )center - establishes a set point (i) generally a portion of brain or spinal cord (ii) increases or decreases activity at an effector (c) effector - can change the value of the variable. (i) generally muscle or glands. (3) Receptor detects the stimulus and informs the control center which analyzes the input from the receptor and send output to the effector and the effector produces a response. (4) Example of blood pressure sensor in carotid sinus (b) integrating center in pons (c) heart is effector (5) Example of temp (Antagonistic effectors - shivering and sweating) sensor - hypothamamus (b) intergrated in brain (c) effectors sweat glands / muscle. Positive Feedback (1) Positive feedback responses are not homeostatic and are rare in healthy individuals. (2) Positive implies that a deviation from normal value occurs and the response of the system is to make the deviation greater. (3) Eg. Blood clotting - activation of one factor causes and avalanche effect -single change can cause a blood clot. (4) Birth of baby...stretch of the uterine cervix causes uterus to contract which causes baby to push against cervix even more which results in the increase contraction of the cervix etc