Major Themes Life is defined by specific characteristics. Form and function are intimately related at every level of life. Life is sustained by specific things in the external environment. Life is maintained by strict, automatic reactions that adjust the internal environment. Precise communication is a key attribute of science and requires specialized descriptive language.
Notes: Types of anatomy: Gross anatomy: structures seen with naked eye Microscopic anatomy: invisible to naked eye Three states: Life: form and function combine to produce biologic activity Illness: abnormal form or function Death: end of biologic activity
Characteristics of life: all living things share four functions: - Organization - Metabolism - Adaptation -Reproduction Question: We shiver when it is cold to generate more heat. Which function of life does this represent? Answer: Adaptation Notes: Organism: complete life form that can function independently of other life forms Organization is maintained by boundaries that separate the internal environment from the external environment. Metabolism involves anabolism and catabolism.
The human hand, with thumb rotated at 90°, is capable of a pincer grip. The monkey hand, with thumb parallel to other fingers, only allows a less precise (but stronger) palmar grip. Question: True or false: the structure of the monkey’s hand refers to its physiology. False; structure refers to anatomy
Question: Which is the smallest building block illustrated in this figure? Answer: atoms
Astronauts carry their life-sustaining environment with them. Question: Which necessities of life are illustrated? Answer: Pressure, oxygen, temperature Notes: Elements we normally get from our environment include pressure, oxygen, heat, water, and nutrients. Pressure includes static pressure (such as atmospheric pressure) and dynamic pressure (e.g., strong wind, blood pressure). Blood pressure is controlled by volume, heart activity, blood vessel diameter Oxygen is about 20% of air. Absorbed by the lungs, it unlocks chemical nutrients from food and keeps cells alive. Body temperature must be maintained within extremely narrow limits, but livable environmental temperature can vary widely. Heat is generated by metabolism, dissipated by radiation, increased when cold by shivering, and decreased when hot by sweating. Nutrients are burned for energy and used as building blocks. Water is a solvent for chemical reactions, smoothes movements of various body parts, carries nutrients to cells and removes wastes, transports messenger and regulatory molecules.
Altitude gradient of a roof Pressure gradient in a blood vessel Concentration gradient in a cell Question: In part B, where is the pressure greatest—inside or outside the blood vessel? Answer: Inside Notes: Gradient: difference in the quantity or concentration of a physical value between two areas
Negative feedback restores homeostasis. Negative feedback is used to maintain a constant temperature in a room (inner circle) and in a person (outer circle). Question: Name the effectors that respond to a change in body temperature. Answer: Sweat glands and blood vessels in skin Notes: Homeostasis depends on negative feedback: process that reflexively keeps systems tightly regulated near their set point and thus promotes stability Set point is optimum range (e.g., 98.6 °F) Sensor detects deviations from set point Deviations trigger opposing (negative) response to return to set point.
The disruptions in homeostasis caused by the bullet are shown in red. Homeostatic adjustments and medical interventions are in yellow. Question: Why was Reagan’s blood pressure low? Answer: Because he lost blood volume Notes: Homeostasis: body’s collective communication and control effort to maintain internal conditions within a narrow, stable physiologic range Example: Cardiovascular system increases blood flow if blood pressure falls. Analogy: Body’s systems work like a symphony. Negative feedback controls thousands of functions, including levels of sodium and potassium in blood, weight, and blood pressure. Homeostasis keeps body stable. Failure of homeostasis causes illness and even death.
Positive feedback reinforces a condition. Positive feedback loops often terminate in cataclysmic events, such as childbirth or death. Question: Would uterine contractions increase or decrease the activation of the cervical nerve endings (the sensors)? Answer: Increase Notes: Positive feedback: increases intensity of effect Unlike negative feedback, positive feedback: - Controls only a few functions - Enhances rather than reduces change - Does not stabilize, but pushes reactions to an ending or to exhaustion Example: childbirth
Directional terms refer to the body in the anatomic position. Question: Which part is more lateral—the ears or the nose? Answer: Ears Notes: Directional terms: describe the position of a part relative to another part or a subdivision of a part Example:Inferior sternum (lower part of breastbone) Example: Incision superior to (above) the fifth rib Based on standard anatomic position
Notes: Medical terms often come from Greek or Latin roots. Prefixes precede the root. Suffixes follow the root.
Transverse plane: one parallel to the horizon that divides structures into superior and inferior parts.
Planes divide the body in specific ways. Cuts along these planes result in different sections. Question: Which plane divides the body into right and left halves? Answer: Sagittal
Regional terms and surface landmarks describe important areas and points on the surface of a body in the anatomical position. Question: What is the adjective describing the entire foot? Answer: Pedal Notes: Surface anatomy: -head: skull and face -neck -trunk or torso: chest, abdomen, pelvis -upper limb: shoulder, armpit, arm, forearm, wrist, hand -lower limb: buttock, thigh, leg, ankle, foot
Body organs exist in hollow spaces lined by membranes. Question: Which cavity is superior—pelvic or abdominal? Answer: abdominal Notes: Dorsal cavities: Cranial cavity: contains the brain Spinal cavity: contains the spinal cord Formed of bone and lined with membranes Ventral cavity: Thoracic cavity: lies above the diaphragm; contains the heart, lungs, and large vessels Abdominopelvic cavity: lies below the diaphragm -Abdominal cavity: contains most of the digestive organs and abdominal glands, such as the stomach, liver, gall bladder, pancreas, and most of the intestines -Pelvic cavity: contains part of the large intestine and reproductive organs
Minute cavities separate the two layers of the pericardium and the two pleurae. The double-layered thoracic membranes formed when the heart and lungs pushed their way into fetal cavities. Question: Name the membrane in contact with the heart wall. Answer: Visceral pericardium Notes: Membranes in the thoracic and abdominopelvic cavities: Pericardium: covers the heart Pleurae: cover the lungs Peritoneum: covers abdominal and pelvic organs Membrane layers: Visceral attaches to organs Parietal attaches to cavity walls
A. Abdominal quadrants Notes: Upper right quadrant: liver Right lower quadrant: appendix Peritoneum: covers abdominal and pelvic organs
B. Abdominal regions Question: Which region is inferior—the iliac or hypochondriac region? Answer: Iliac Notes: Abdominal regions: -Two horizontal lines below ribs and above hip bones -Two vertical lines near nipples
Notes: Remember—both acute and chronic diseases can range in severity from mild to life-threatening.