Question

Describe the anatomical structures and physiological events that allow you to perceive the warmth of the sun.

Answer 1

An ideal answer should be the thermoreceptors, which are distributed throughout the skin, must be present to sense the thermal stimuli. The warmth from the sun stimulates the warm thermoreceptors to become activated by warming the receptive field of thermoreceptors and stimulating the production of graded potentials. When the graded potentials reach the threshold, they trigger nerve impulses in the themoreceptor, which serves as a first-order neuron that transmits the information to the CNS where a second-order neuron conducts impulses via neurons of the spinothalamic tract to the thalamus. From the thalamus, third-order neurons conduct impulses to the primary somatosensory area of the cerebral cortex where the impulses are perceived as a feeling of warmth.

Answer 2

Answer: C. cell bodies of sensory neurons

Answer 3

Ans: False

Answer 4

Answer: Skin

Answer 5

Answer: portocaval anastamosis is the anastamosis between the portal circulation and systemic circulation.

The normal function o fthe portal vein is to carry deoxygenatd blood from the Gastrointestinal tract to liver for detoxification.But when there is any block in the portal circulation the blood should reach the systemic circulation,it is done by this portocaval anastamosis.

One of the potential site of portocaval anastamosis is lower part of the esophagus.

Left gastric vein (branch of portal vein ) anastamose with the lower esophageal vein of azgous vein.

So, when there is any blockage in the portal circulation ,it can cause swelling over the lower part of the esophagus and it is called esophageal varices.

Other portocaval anastamosis are

Lower part of the rectum: anastamosis between superior rectal vein (portal branch) with middle and inferior rectal veins. swelling is called Hemorrhoid.

paraumbilical regin : between the para umbilical vein and superiorepigastric vein

Retroperitoneal :colic vein (portal branch) with veins of posterior abdominal wall

patent ductus venosis: left branch of the portal vein and inferior venecava