Excretion And Homeostasis Flashcards
Define the process of excretion
The process of removing waste from the body
Substance(s) excreted from the lungs?
Carbon dioxide
Cater vapour
Substance(s) excreted from the skin?
Salts, water
Substance(s) excreted from the kidneys?
Urea
Water
Describe the process of ultrafiltration
The hydrostatic pressure forces small molecules such as water, glucose, amino acids, sodium chloride and urea through the filter from the blood in the glomerular capsule into the bowman’s capsule
Describe the process of selective reabsorption
In the proximal tubule
all the glucose is returned to the blood
Some of the salts are reabsorbed
In the loop of henle
Some of the water is reabsorbed
Active transport
The role of ADH?
Regulates the water content of the blood
From the pituitary gland
Released if the water content is too low
This causes the kidney to reabsorb more water
Less ADH is released if the water content in the blood is too high
The role of the collecting ducts?
By osmosis
Causes water to be reabsorbed
Describe the composition of urine
About 95% water
5% urea
What ways does the skin regulate temperature?
Sweating
Vasodilation
Vasoconstriction
How does sweating help with temperature regulation?
When the body is too cold the skin forms an impermeable surface
When the body is too hot sweat glands produce more sweat that evaporates from the skin using the body’s heat energy
Role of vasodilation in temperature regulation?
The capillary loops near the surface of the skin dilate
More heat is lost
Keeps you cool
Role of vasoconstriction in temperature regulation?
The arterioles leading to the surface capillary loops constrict and blood flow to the surface of the skin is reduced so that less heat is lost
Constricted by sphincter muscles
