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Chapter 1 - Introduction to the Human Body
Objectives
1. Define anatomy and physiology, and name several sub-disciplines...
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I. A & P defined
Anatomy = study of structures by dissection, imaging, and microscopy
• macro - gross & systemic, embryo...
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3. An organ is composed of several tissues that accomplish a specific
function
ex: stomach is lined with specialized epi...
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Systems
1. Integument = skin, linings, hair, nails, sweat/oil glands
fx: -barrier between environment & internal tissues...
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III. Life is recognized by certain characteristics:
• Metabolism: the sum of chemical processes in an organism
Anabolism...
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IV. Homeostasis is the normal, healthy, adult state = equilibrium
A major mechanism for homeostasis is communication and...
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3. Feedback systems always involve 3 components:
receptor - senses the stimulus
control center - interprets the stimulus...
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Dissection planes
sagittal divides right from left
coronal = frontal divides front from rear
transverse divides superior...
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VI. Body Cavities
Dorsal (rear) cavity contains cranial cavity (brain)
vertebral canal (spinal column)
Ventral (front) c...
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Introduction to human body

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Introduction to human body

  1. 1. 1 Chapter 1 - Introduction to the Human Body Objectives 1. Define anatomy and physiology, and name several sub-disciplines of these sciences. 2. Describe the levels of structural organization that make up the human body. 3. Define the eleven systems of the human body, the organs present in each, and their general functions. 4. Define the important life processes of the human body. 5. Describe the components of a feedback system. 6. Contrast the operation of negative and positive feedback systems. 7. Describe the orientation of the body in the anatomical position. 8. Relate the common names to the corresponding anatomical descrip- tive terms for various regions of the human body. 9. Define the anatomical planes and sections and the directional terms used to describe the human body. 10. Describe the principal body cavities, the organs they contain, and their associated linings. 11. Name and describe the nine abdominopelvic regions and the four abdominopelvic quadrants.
  2. 2. 2 I. A & P defined Anatomy = study of structures by dissection, imaging, and microscopy • macro - gross & systemic, embryology & development • micro - cytology, histology Physiology = study of functions by chemical and physical means cells organs systems [Pathology = study of anatomy and physiology during illness or after death] II. Levels of Organization chemicals → cells → tissues → organs → systems (epithelial, (contain (accomplish muscle, several a complete connective, types of function) nervous) tissues) 1. A cell is the basic unit of life in which functional substances and parts are dissolved or suspended in fluid cytosol, and surrounded by functional membranes made of lipids and proteins. 2. A tissue is an organized group of cells of different types as well as their extracellular material (called matrix) there are only 4 classes of tissue : • epithelial tissue covers surfaces (e.g., skin, lining of body cavities, lining of hollow organs like bladder, stomach) • muscle tissue performs work or alters the shape of an organ • nervous tissue includes neurons and their support cells (called neuroglia) • connective tissue is all the rest (e.g., blood cells, bone & cartilage cells) cells & matrix that fill body spaces and bind tissues together
  3. 3. 3 3. An organ is composed of several tissues that accomplish a specific function ex: stomach is lined with specialized epithelium, surrounded by connective tissue that contains blood vessels and nerves, surrounded by 3 layers of smooth muscle, covered with another layer of epithelium and connective tissue that holds it in place. Working together, the tissues accomplish the function of grinding, dissolving, and partially digesting food. 4. A system is composed of several organs. ex: the digestive system includes the mouth (chew and moisten food), esophagus (deliver food to stomach), stomach (grind and dissolve food), small intestine (finishes digesting food and absorbs nutrients), large intestine (reabsorbs water to prevent loss), and rectum (stores feces). 5. An organism is one unit of life. ex: Homo sapiens, Canis familiaris, Saccharomyces cerviseae
  4. 4. 4 Systems 1. Integument = skin, linings, hair, nails, sweat/oil glands fx: -barrier between environment & internal tissues/organs - interacts with environment (temp regulation, H2O & waste secretion) - performs one of the steps in synthesis of vitamin D 2. Skeletal = bones, joints & cartilage fx: - support and provide fulcrum for movement - calcium reservoir - generates blood cells 3. Muscular = skeletal, cardiac, smooth fx: - movement & posture - generates body heat 4. Nervous = brain, spinal cord, peripheral nerves, sense organs fx: - monitors internal & external environment, and generates appropriate responses - communicates by means of action potentials (electrical) 5. Endocrine = organs & tissues that produce hormones fx: - monitors internal environment, and acts on other organs/tissues to produce appropriate response - communicates through blood using chemical reactions on the target organ 6. Cardiovascular = heart, vessels, blood (plasma) fx: - distributes nutrients (including O2) - delivers wastes for removal (including CO2) - prevents excessive bleeding - regulates pH and temperature 7. Lymphatic & Immune = lymph fluid, lymph vessels, organs which generate & modify lymphocytes fx: - transports fluids & nutrients - participates in production, maturation & specificity of immune cells - produces antibodies & cytokines 8. Respiratory = lungs & associated passageways (bronchi, trachea, pharynx) fx: - transports gases (O2, CO2, H2O-vapor) - regulates pH and temperature - produces vocal sounds 9. Digestive = GI tract (esophagus, stomach, small & large intestines), and associated organs (salivary glands, liver & gall bladder, pancreas) fx: - prepares ingested food for absorption - eliminates external solid wastes - produces hormones 10. Urinary = kidneys, ureters, bladder, urethra fx: - eliminates internal, soluble wastes - regulates pH and water balance - produces hormones 11. Reproductive = organs (ovary, testis) that produce gametes, & accessory organs (Fallopian tubes, uterus, epididymis, vas deferens, penis) fx:- produces gametes - produces hormones - houses & nourishes fetus
  5. 5. 5 III. Life is recognized by certain characteristics: • Metabolism: the sum of chemical processes in an organism Anabolism = chemical reactions that build-up or synthesize Catabolism = chemical reactions that break-down or fragment Equilibrium exists when the organism is in "steady state", i.e., amount of anabolism equals amount of catabolism. ex: healthy adult is in steady state ex: growing healthy child is in anabolic state • Responsiveness: ability to detect and respond to external stimuli ex: afferent nervous system monitors external environment, and then the efferent nervous system alters the body to accommo- date the environment. • Movement: displacement of the whole organism as well as rear- rangement of the relative positions of the organism's parts ex: skeletal muscle impels legs to run ex: smooth muscle causes intestine to move food along. • Growth: increase in organism size (may be cyclical as in bacteria) caused when anabolism exceeds catabolism. • Differentiation is mostly present in multicellular organisms. Dif- ferent cells or tissues or organs specialize to perform one function and lose the ability to perform any other function. ex: lymphocytes in the blood detect and respond to foreign materials in the body (e.g., bacteria); they are not able to carry oxygen or phagocytose debris or cause the blood to clot. • Reproduction: forming new cells to replace damaged or senescent cells or even to "replace" the whole organism. ex: sperm and ova can result in a baby; ex: "stem cells" in your epidermis can reproduce to replace the damaged epithelium when you injure your skin
  6. 6. 6 IV. Homeostasis is the normal, healthy, adult state = equilibrium A major mechanism for homeostasis is communication and exchange of materials between intracellular fluid (ICF), interstitial fluid (between cells) and plasma (the liquid portion of blood). (Extracellular fluid (ECF) = plasma plus interstitial fluid.) 1. A major mechanism for homeostasis is "negative feedback" Negative Feedback: a specific stimulus causes a specific response, and the response "fixes" (i.e., reverses) the stimulus. Stimulus and response mechanisms are commonly hormones and nerves ex: stimulus is scary situation, response is secretion of hormone adrenalin which sends blood and oxygen to heart, lungs, and muscles so you can escape, result is decrease in adrenalin due to escape from the original stimulus; blood and O2 transport return to resting state ex: sensors in the tendons of your legs detect stretching when you are about to lose your balance, reflex neuron causes contraction of the muscle attached to the tendon, muscle pulls you upright & releases the stretch stimulus, result is restoration of balance 2. Positive feedback: specific stimulus causes a specific response that makes the stimulus even stronger → even stronger response…. note: this can be a vicious circle unless something else ("termination mechanism") intervenes. ex: stretching of cervix during childbirth stimulates secretion of hormone (oxytocin) which causes uterus to contract and stretch the cervix even more, etc. Here the "termination mechanism" is baby's birth which inter- rupts the feedback by eliminating the source of cervical stretching.
  7. 7. 7 3. Feedback systems always involve 3 components: receptor - senses the stimulus control center - interprets the stimulus & determines response effector - produces the response If any of the 3 components is missing or malfunctions, then the feedback system won't work. ex: Site in the hypothalamus of the brain is responsible for keeping the body at 37o C (98.6o F) by regulating heat loss through the skin, breath, etc. When bacterial toxins are released into the body, chemicals called prostaglandins are produced which cause the hypothala- mus to set the equilibrium temp at a higher value. ∴ bacterial infections cause fever (“failure” of temperature equilibrium). V. Anatomical Terms (See Fig 1.5) "Anatomical Position" =standing, facing observer, palms forward., feet flat prone = face down supine = face up Major body sections: head cephalic neck cervical trunk thoracic abdominal pelvic arm brachial wrist/hand carpal leg femoral crural ankle/foot tarsal Anatomic Directions: below/above inferior/superior caudal/cephalic nearest/farthest proximal/distal front/rear anterior/posterior ventral/dorsal central/side medial/lateral
  8. 8. 8 Dissection planes sagittal divides right from left coronal = frontal divides front from rear transverse divides superior from inferior Divisions of abdominal-pelvic cavity: RUQ, LUQ, RLQ, LLQ are divided by sagittal & transverse planes through umbilicus. Alternative nomenclature: R & L hypochondriac areas are lateral to epigastric area R & L lumbar areas are lateral to umbilical area R & L iliac (inguinal) areas are lateral to hypogastric (pubic) area (see Fig 1.12)
  9. 9. 9 VI. Body Cavities Dorsal (rear) cavity contains cranial cavity (brain) vertebral canal (spinal column) Ventral (front) cavity is filled with visceral organs and lined by serous or mucous membranes (serous = closed cavity; mucous = open cavity) superior portion = thoracic cavity separated by inferior portion = abdominal-pelvic cavity diaphragm thoracic cavity contains: 2 pleural cavities - contain lungs; lined by pleural membranes mediastinal space -contains trachea, esophagus, blood vessels & lymph vessels pericardial cavity –contains heart; lined by pericardial membranes abdominal-pelvic cavity lined by peritoneal membrane: abdominal cavity contains spleen, pancreas, liver, gall bladder, everything above stomach, the pelvic rim small intestine, proximal part of large intestine. pelvic cavity contains distal part of large intestine (sigmoid colon & rectum), gonads and accessory reproductive organs, bladder (note: kidneys are in abdominal cavity)

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