Author Question: External respiration involves the A) movement of air into and out of the lungs. B) diffusion of ... (Read 86 times)

sdfghj · **on:** Feb 28, 2019

External respiration involves the
A) movement of air into and out of the lungs.
B) diffusion of gases between the interstitial fluid and the external environment.
C) exchange of dissolved gases between the cells and interstitial fluids.
D) binding of oxygen by hemoglobin.
E) utilization of oxygen by tissues to support metabolism.

Question 2

What effect would cutting the vagus nerve branch that innervates the stomach have on gastric function?

courtney_bruh · **Reply #1 on:** Feb 28, 2019

Answer to Question 1

B

Answer to Question 2

The vagus nerve carries parasympathetic preganglionic fibers to many organs within the ventral cavity, including the digestive organs. It stimulates gastric motility and secretion of acid and enzymes. Removing the vagus innervation will eliminate parasympathetic stimulation, leaving only sympathetic innervation, which is inhibitory. This procedure will thus greatly reduce gastric activity. Hormonal stimulation will remain but higher centers will no longer influence secretion of gastric juice.