The Human Body: An Orientation

Physiology/Intro%20to%20Anatomy% 20and%20Physiology/TheAmazingHu manBody.mov Physiology/Intro%20to%20Anatomy% 20and%20Physiology/TheAmazingHu manBody.mov Physiology/Intro%20to%20Anatomy% 20and%20Physiology/TheAmazingHu manBody.mov Physiology/Intro%20to%20Anatomy% 20and%20Physiology/TheAmazingHu manBody.mov

Anatomy The study of the structures or parts of the body. Physiology The study of the function of the body. (How the parts work.)

Anatomy – Levels of Study Gross Anatomy ––L––Large structures ––E––Easily observable

Anatomy – Levels of Study Microscopic Anatomy ––V––Very small structures ––V––Viewed with a microscope

Levels of Structural Organization Atoms form molecules Atoms form molecules Molecules form cells (the smallest units of living things) Molecules form cells (the smallest units of living things) A tissue consists of cells working together to perform a common function A tissue consists of cells working together to perform a common function

Levels of Structural Organization An organ consists of 2 or more tissues working together An organ consists of 2 or more tissues working together An organ system is a group of organs working together An organ system is a group of organs working together An organism consists of organ systems working together An organism consists of organ systems working together

Organ Systems Integumentary System Integumentary System Forms the external body covering and protects the internal organs from infection. Forms the external body covering and protects the internal organs from infection. Includes skin, hair and nails. Includes skin, hair and nails.

Organ Systems Skeletal System Skeletal System Functions in Movement and Support Functions in Movement and Support Includes bones, cartilage, ligaments Includes bones, cartilage, ligaments

Organ Systems Muscular System Muscular System Functions in movement of the body and through the body Functions in movement of the body and through the body Includes three types of muscles Includes three types of muscles Skeletal, cardiac and smooth (visceral) Skeletal, cardiac and smooth (visceral)

Organ Systems Nervous System Nervous System Fast acting control system Fast acting control system Also functions in communication Also functions in communication Includes brain, spinal cord and nerves Includes brain, spinal cord and nerves

Organ Systems Endocrine System Endocrine System Slower acting control system of the body Slower acting control system of the body Glands secrete hormones to regulate the body Glands secrete hormones to regulate the body

Organ Systems Cardiovascular System Cardiovascular System Transports materials through the body via the bloodstream Transports materials through the body via the bloodstream Includes heart and blood vessels Includes heart and blood vessels

Organ Systems Lymphatic System – –Returns tissue fluid to blood vessels – –Important in immunity

Organ Systems Respiratory System – –Supplies oxygen and removes carbon dioxide – –Includes lungs, trachea, etc.

Organ Systems Digestive System – –Digestion of food for absorption of nutrients – –Includes stomach, intestines, etc

Organ Systems Urinary System – –Filters toxins from the blood – –Includes kidneys, bladder, etc.

Organ Systems Reproductive Systems – –Produces offspring – –Includes male and female genitalia

Necessary Life Functions 1. Maintaining boundaries between internal and external environments –Plasma membranes –Skin 2. Movement (contractility) –Of body parts (skeletal muscle) –Of substances (cardiac and smooth muscle)

Necessary Life Functions 3. Responsiveness: The ability to sense and respond to stimuli –Withdrawal reflex –Control of breathing rate 4. Digestion –Breakdown of ingested foodstuffs –Absorption of simple molecules into blood

Necessary Life Functions 5. Metabolism: All chemical reactions that occur in body cells –Catabolism and anabolism 6. Excretion: The removal of wastes from metabolism and digestion – Urea, carbon dioxide, feces

Necessary Life Functions 7. Reproduction –Cellular division for growth or repair –Production of offspring 8. Growth: Increase in size of a body part or of organism

Survival Needs 1. Nutrients –Chemicals for energy and cell building –Carbohydrates, fats, proteins, minerals, vitamins 2. Oxygen –Essential for energy release (ATP production)

Survival Needs 3. Water –Most abundant chemical in the body –Site of chemical reactions 4. Normal body temperature –Affects rate of chemical reactions 5. Appropriate atmospheric pressure –For adequate breathing and gas exchange in the lungs

Homeostasis Maintenance of a stable internal environment – –Temperature, fluid levels, pH, etc. Must be maintained for normal functioning and to sustain life Homeostatic imbalance – can result in disease or death

Maintaining Homeostasis The body communicates through nervous and endocrine systems consisting of 3 basic components 1) Receptor Detects a stimulus 2) Control center Analyzes information Determines appropriate response 3) Effector (Muscles or glands) Responds to the stimulus

Metabolism – all chemical reactions within the body – –Production of energy – –Making body structures Maintaining Homeostasis

Feedback Mechanisms Negative feedback – –Includes most homeostatic control mechanisms – –The response shuts itself off when it reaches the setpoint. – –Example: Household thermostat

Figure 1.5 Sweat glands activated Shivering begins Stimulus Body temperature rises BALANCE Information sent along the afferent pathway to control center Information sent along the afferent pathway to control center Afferent pathway Afferent pathway Efferent pathway Efferent pathway Information sent along the efferent pathway to effectors Information sent along the efferent pathway to effectors Stimulus Body temperature falls Receptors Temperature-sensitive cells in skin and brain Receptors Temperature-sensitive cells in skin and brain Effectors Sweat glands Effectors Skeletal muscles Control Center (thermoregulatory center in brain) Control Center (thermoregulatory center in brain) Response Evaporation of sweat Body temperature falls; stimulus ends Response Body temperature rises; stimulus ends

Negative Feedback: Regulation of Blood Volume by ADH Receptors sense decreased blood volume Receptors sense decreased blood volume Control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH) Control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH) ADH causes the kidneys (effectors) to return more water to the blood ADH causes the kidneys (effectors) to return more water to the blood

Feedback Mechanisms Positive feedback – –Increases the intensity of the original stimulus until ultimate goal is reached – –In the body, this only occurs in blood clotting and birth of a baby

Feedback cycle ends when plug is formed. Positive feedback cycle is initiated. Positive feedback loop Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. Released chemicals attract more platelets. Platelet plug forms Figure 1.6

Positive feedback cycle is initiated. Break or tear occurs in blood vessel wall. 1 Figure 1.6, step 1

Positive feedback cycle is initiated. Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. 1 2 Figure 1.6, step 2

Positive feedback cycle is initiated. Positive feedback loop Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. Released chemicals attract more platelets Figure 1.6, step 3

Feedback cycle ends when plug is formed. Positive feedback cycle is initiated. Positive feedback loop Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. Released chemicals attract more platelets. Platelet plug forms Figure 1.6, step 4

Body Membranes The organs within the cavities are surrounded by a type of two layered membrane called the SEROUS MEMBRANE The organs within the cavities are surrounded by a type of two layered membrane called the SEROUS MEMBRANE The outer layer of each membrane is called the PARIETAL layer and forms a "lining" against the inner wall of each cavity The outer layer of each membrane is called the PARIETAL layer and forms a "lining" against the inner wall of each cavity

The inner layer of each membrane covers the surface of each organ and is called the VISCERAL layer

Membranes: Membranes: 1. Pleura (or pleural membrane) - surrounds the lungs --outer layer = parietal pleura --inner layer = visceral pleura 1. Pleura (or pleural membrane) - surrounds the lungs --outer layer = parietal pleura --inner layer = visceral pleura 2. Pericardium (or pericardial membrane) - surrounds the heart --outer layer = parietal pericardium --inner layer = visceral pericardium 2. Pericardium (or pericardial membrane) - surrounds the heart --outer layer = parietal pericardium --inner layer = visceral pericardium

3. Peritoneum (or peritoneal membrane) - surrounds all the organs within the abdominopelvic cavity --outer layer = parietal peritoneum --inner layer = visceral peritoneum 3. Peritoneum (or peritoneal membrane) - surrounds all the organs within the abdominopelvic cavity --outer layer = parietal peritoneum --inner layer = visceral peritoneum Between the layers of each membrane is a lubricating fluid which is called SEROUS FLUID Between the layers of each membrane is a lubricating fluid which is called SEROUS FLUID