Human and Animal Physiology: Energy Metabolism, Thermoregulation, Foraging, and Digestion

Flashcards covering energy metabolism, thermoregulation, optimal foraging, comparative digestive anatomy, and gastrointestinal regulation.

What is the complete chemical reaction equation and net ATP yield for the aerobic oxidation of one molecule of glucose?

The chemical reaction equation is $C_6H_{12}O_6 + 6 O_2 + 32 ADP + 32 P_i \rightarrow 6 CO_2 + 6 H_2O + 32 ATP$, yielding a net total of $32\text{ ATP}$ per glucose molecule.

What percentage of released energy is captured as ATP during aerobic glucose oxidation versus lost as heat?

Approximately $32.6\%$ (or $32.7\%$) of the energy ($224\text{ kcal}$ out of $686\text{ kcal}$) is captured in ATP, while the remaining $67.3\%$ ($462\text{ kcal}$) is dissipated as body heat.

Which pancreatic islet cells secrete insulin and glucagon, and what blood glucose levels define normal, hyperglycemic, and hypoglycemic states?

Beta cells secrete insulin and alpha cells secrete glucagon. Normal blood glucose levels range from $70\text{--}110\text{ mg/dL}$, hyperglycemia is defined as glucose $> 140\text{ mg/dL}$, and hypoglycemia is defined as glucose $< 60\text{ mg/dL}$.

What are the four physical mechanisms of environmental heat exchange involved in thermoregulation?

1. Radiation (mainly infrared heat exchange), 2. Evaporation (conversion of liquid to gas for heat loss), 3. Convection (heat exchange with a moving gas or liquid), and 4. Conduction (direct heat transfer between contacting objects).

What is the core premise of Optimal Foraging Theory?

It is a model stating that animals select food types, locations, and time investments to maximize net energy uptake while minimizing effort, providing a surplus of energy for reproduction and evolutionary success.

What are the primary advantages and disadvantages of foregut fermentation compared to hindgut fermentation?

Foregut fermentation allows highly efficient cellulose digestion, utilization of microbial protein, and toxin breakdown, but results in slow passage of food. Hindgut fermentation permits rapid food processing and high-volume intake, but has lower fiber digestion efficiency and reduced utilization of microbial protein.

What functional advantage does the evolution of the secondary palate provide to mammals?

The secondary palate physically separates the oral cavity from the nasal cavity, enabling mammals to chew food and breathe simultaneously.

What are the four fundamental tissue layers of the gastrointestinal tract wall listed from innermost to outermost?

1. Mucosa (surrounding the lumen), 2. Submucosa (connective tissue layer), 3. Muscularis externa (smooth muscle layer), and 4. Serosa (outermost connective tissue layer).

Which specific stomach mucosa cells secrete hydrochloric acid ($HCl$) and pepsinogen?

Parietal cells in the gastric glands secrete hydrochloric acid ($HCl$) and intrinsic factor, whereas chief cells secrete the zymogen pepsinogen.

How do secretin and cholecystokinin (CCK) regulate exocrine pancreatic secretions in response to duodenal stimuli?

Duodenal acid ($H^+$) stimulates secretin release to prompt pancreatic duct cells to secrete bicarbonate-rich fluid. Fat and protein digestion products in the duodenum stimulate CCK release to prompt pancreatic acinar cells to secrete digestive enzymes.