Homeostasis & Excretion

Homeostasis is...

• the maintenance of a constant internal environment.

• the process by which metabolic waste and other substances are removed from the body.

• The process by which living organisms take in materials necessary for growth and energy.

• The chemical reactions that take place inside cells and release energy from the breakdown of nutrients.

A man is lost in the desert. Reorder the following processes to describe the changes to his body.

• Increase in body temperature

• Normal body temperature

• Vasodilation

• Thermoreceptors in the hypothalamus and skin detect change

• Decrease in body temperature

​ (a)   in the ​ (b)   and ​ (c)   detect changes in temperature in the body.

• thermoreceptors
• hypothalamus
• skin
• chemoreceptors
• nerve axions
• liver
• pituitary
• thyroid
• pancreas
• heart

Select all of the changes which occur when a person has an increase in body temperature.

• Increased sweating

• Vasodilation

• Vasoconstriction

• Hairs lie flat against skin

• Skin hairs erect

Label this diagram to show the processes involved in vasodilation.

e

f

g

h

Sweat glands stop working

Heat loss by convection

Vessels dilate, increase blood flow

Sweat glands excrete sweat

Hair erector muscles contract

Hair erector muscles relax

Vessels constrict, lower blood flow

Heat loss by radiation

Label this diagram to show the processes involved in vasoconstriction.

h

d

b

a

Heat loss by convection

Hair erector muscles relax

Hair erector muscles contract

Trapped air is a great insulator

Heat loss by radiation

Vessels dilate, increase blood flow

Hairs stand upright trapping air

Sweat glands excrete sweat

Vessels constrict, lower blood flow

Which of these functions is not a major function of the kidneys?

• Filtration

• Selective reabsorption

• Osmoregulation

• Excretion

• Respiration

What is the name of the tube which carries urine from the kidneys to the bladder for excretion? (Watch spelling!)

The ​ (a)   carries ​ ​ (b)   blood to the ​ (c)   in the kidney.

• renal artery
• oxygenated
• Bowman's capsule
• renal vein
• aorta
• nephron
• deoxygenated
• loop of Henle

Reorder the following steps to show the changes which occur in the body when the brain detects that the blood is too concentrated.

• Smaller volume of more concentrated urine.

• Increased permeability to water.

• Pituitary gland releases ADH into the pancreas.

• Water moves into the blood.

• Travels through bloodstream to kidney tubules.