Animal Physiology Review - Lectures 24-33

Comprehensive vocabulary flashcards covering animal nutrition, digestive systems, metabolic rates, thermal regulation, locomotion, and reproductive physiology based on Lectures 24-33.

Tissue Maintenance

Energy required for cellular repair and general upkeep.

Energy Equivalents of Macronutrients

Fats ($9\,kcal/g$), Proteins ($4\,kcal/g$), and Carbohydrates ($4\,kcal/g$).

Batch Reactor (2-Way Gut)

A gastrovascular cavity with a single opening where food is ingested, digested, and egested in discrete batches; found in Cnidarians and Platyhelminthes.

Plug Flow Reactor (1-Way Gut)

A continuous tube with a separate mouth and anus allowing for continuous, efficient one-way processing of food.

Cranial Kinesis

Independent movement of jaw bones connected by elastic ligaments, allowing snakes to swallow prey larger than themselves.

Gastric Mills

Serrated "jaws" inside the stomach of decapods (like crayfish) controlled by smooth muscle to grind hard prey.

Gastroliths

Pebbles ingested by birds that aid the muscular, keratinized gizzard in grinding seeds.

Foregut

The region of the vertebrate GI tract including the esophagus and stomach, primarily responsible for storage and initial breakdown at a pH < 2.

Parietal Cells

Specialized cells in gastric pits that secrete Hydrochloric Acid ($HCl$).

Chief Cells

Cells in the stomach that secrete Pepsinogen, which is an inactive protease.

Bile

A substance produced by the liver and stored in the gallbladder that acts as a detergent to emulsify fats.

Hepatopancreas

A single organ in many mollusks and crustaceans that performs the functions of both the liver and the pancreas.

Chloragogen Tissue

Tissue found in annelids (earthworms) that functions similarly to a liver for glycogen storage and detoxification.

Chylomicrons

Packages of broken-down fats that enter the lacteals (lymphatic system) rather than the blood directly.

Abomasum

The "true" glandular stomach in ruminants where microbes are digested for protein.

Myenteric Plexus

The part of the Enteric Nervous System located between muscle layers that controls peristalsis.

CCK (Cholecystokinin)

A hormone stimulated by fats and proteins in the small intestine that triggers the release of bile and pancreatic enzymes.

Ghrelin

The "hunger hormone" secreted by an empty stomach to stimulate appetite.

Kleiber’s Law (3/4 Power Law)

An allometric scaling relationship defined as $MR = a \cdot M^{0.75}$.

Convection

Heat transfer via moving air or water; water has $30\times$ higher thermal conductivity and $4.2\times$ higher specific heat capacity than air.

Regional Heterothermy

A thermal strategy where parts of the body are kept at different temperatures, such as a bird's legs versus its core.

Thermoneutral Zone (TNZ)

The range of ambient temperatures for endotherms where the metabolic rate is minimal and steady.

Rete Mirabile

A countercurrent heat exchanger where warm arterial blood transfers heat to cool venous blood to prevent core cooling.

Brown Adipose Tissue (BAT)

Specialized fat containing a high density of mitochondria and $UCP1$ (Thermogenin) for non-shivering thermogenesis.

Homeoviscous Adaptation

The process where animals in cold environments increase unsaturated fatty acids in cell membranes to maintain fluidity.

Supercooling

A freeze avoidance strategy where fluids stay liquid below $0^{\circ}C$ by excluding nucleators.

Pejus Range

The temperature range where an organism's performance begins to decline before reaching lethal limits.

Reynolds Number (Re)

A dimensionless value representing the ratio of inertial forces to viscous forces; $Re = \frac{\text{inertial}}{\text{viscous}}$.

Root Effect

A phenomenon where hemoglobin drops $O_2$ at low $pH$, allowing physoclist fishes to move gas into the swim bladder.

Tiktaalik

A transitional fossil known as the "Fishapod" that possessed a neck, wrists, and ribs but remained primarily aquatic.

Carrier’s Constraint

The physiological limitation where animals with a sprawled posture cannot breathe while running due to lateral undulation compressing the lungs.

Mechanical Advantage (MA)

The ratio of the Force Arm ($FA$) to the Weight Arm ($WA$) in a skeletal lever system ($MA = \frac{FA}{WA}$).

Indirect Flight Muscles

Flight muscles in advanced insects that attach to the thorax exoskeleton rather than the wings, powering strokes by deforming the thorax.

Supracoracoideus

The avian flight muscle responsible for powering the upstroke.

Aspect Ratio ($\Lambda$)

The ratio used to describe wing shape; high aspect ratio wings are long and narrow, optimized for gliding.

Protandry

A form of sequential hermaphroditism where an organism starts as a male and changes to a female, such as in clownfish.

Vitellogenesis

The process of yolk formation in female breeding fish, triggered by the release of Estradiol-$17\beta$ ($E2$).

Corpus Luteum (CL)

An endocrine structure formed after ovulation that secretes estrogen and progesterone to mature the uterine endometrium.

Prolactin

A hormone that stimulates milk production in mammary alveoli and drives parental care instincts.

Oxytocin

The hormone that triggers the milk letdown reflex through myoepithelial contraction and strengthens social bonds.