ap bio 3

Regulation

coordination and control of body systems; nervous system involves electrochemical messages (neurotransmitters) and endocrine system involves chemical signals (hormones)

Gills

used for gas exchange in many aquatic species; grow larger to increase surface area for gas exchange

Interstitial fluid

site of exchange between blood and body cells

Epithelial tissue

lines outer surfaces and exchange surfaces in multicellular organisms

Muscle tissue

contractions involve interactions between actin and myosin

Cardiac muscle

striated and had intercalated disks

Negative feedback

returns a variable to a normal range like a thermostat; ex: insulin produced in response to increased blood sugar levels

Positive feedback

amplifies a stimulus; ex: contractions during labor increase in intensity and frequency until delivery

Homeostasis

maintaining a constant internal environment

Ectotherm

animals that gain heat from external sources; include most invertebrates, fishes, amphibians, and reptiles; they are more likely to survive long periods of food deprivation than endotherms because they do not invest much energy in temperature regulation

Endotherm

animals that generate heat by metabolism; include birds and mammals; at a disadvantage in locations that have limited food sources

Hypothalamus

temperature regulating center of vertebrates

Metabolic rate

amount of energy an animal uses in a unit of time; can be determined by animal’s heat loss, amount of oxygen consumed or carbon dioxide produced, and measuring energy content of food consumed and energy lost in waste products

Ingestion

process of obtaining food

Complete digestive system

allows for specialized regions with special functions

Essential nutrients

materials that an animal cannot assemble from simpler organic molecules

Carbohydrates

main source of food energy; when digested, absorbed directly into the bloodstream

Proteins

breakdown into amino acids; needed in the diet because they serve a variety of functions and organisms’ bodies do not store excess proteins

Fats

breakdown into fatty acids and glycerol; when digested, most absorbed fat enters the lymphatic system before entering the blood

Hydrolysis

using water molecules to break bonds; used for digestion of nutrients

Mechanical digestion

break down food into smaller pieces to increase surface area for chemical digestion

Peristalsis

smooth, wavelike contractions of the digestive system that begins in the esophagus

Stomach

location where food is stored until digestion; highly acidic environment

Small intestine

secretin is released to increase flow of bicarbonate ions from the pancreas so stomach acid in food can be neutralized

Villi

found lining the small intestine to increase surface area for absorption of nutrients; covered in microvilli that also increase surface area

Mucins

glycoproteins released by salivary glands that make food slippery so it slides through digestive system easily

Bile

produced by the liver, stored in the gallbladder; emulsify fats in the duodenum

Intestinal bacteria

needed to assist with digestion of certain foods and production of certain vitamins such as vitamin K

Dentition

analysis of teeth shape to determine what kind of foods the animal eats; sharp, scissor-like teeth would tear at flesh; large flat molars would chew plants

Open circulatory system

organs are bathed in blood because blood is not always confined to blood vessels; has lower pressure than found in closed circulatory systems

Blood flow

superior and inferior vena cava to right atrium to right ventricle out pulmonary artery to lung to get oxygen; from lung to left atrium to left ventricle through aorta to the body to deliver oxygen

Sinoatrial node

pacemaker of the heart; determines rate and timing of cardiac muscle contractions

Velocity of blood flow

lowest in capillaries because total cross-sectional area of capillaries is greater than total cross-sectional area of any other part of the circulatory system

Lymphatic vessels

returns fluid that leaks out of capillary beds ; when blocked, more fluid will accumulate in interstitial areas

Hemoglobin

pigment in red blood cells that binds to oxygen to transport it throughout the body; oxygen must cross into and out of the cells lining the lungs, into and out of endothelial cells lining an alveolar capillary, and finally into a red blood cell to bind to hemoglobin

Blood clotting

involve cell fragments called platelets; a cascade of complex reactions that converts prothrombin to thrombin which then converts inactive fibrinogen to fibrin

Countercurrent exchange

blood flows in opposite direction to water passing over the gills; evident in flow of water across gills of a fish and blood within the gills

Bird breathing

air passes through lungs in one direction only; gas exchange occurs during inhalation and exhalation to meet metabolic demands of flight

Human breathing

regulated by involuntary mechanisms; control center in the medulla oblongata regulates rate in response to pH changes in cerebrospinal fluid; blood pH falls due to rising carbon dioxide levels

Carbon dioxide

enzyme in red blood cells converts carbon dioxide into bicarbonate ions