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

• Decrease in body temperature

• Vasodilation

• Thermoreceptors in the hypothalamus and skin detect change

• Normal 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

Hair erector muscles relax

Sweat glands stop working

Vessels constrict, lower blood flow

Heat loss by convection

Heat loss by radiation

Hair erector muscles contract

Vessels dilate, increase blood flow

Sweat glands excrete sweat

Label this diagram to show the processes involved in vasoconstriction.

h

d

b

a

Trapped air is a great insulator

Heat loss by convection

Hairs stand upright trapping air

Hair erector muscles contract

Vessels dilate, increase blood flow

Heat loss by radiation

Hair erector muscles relax

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.

• Water moves into the blood.

• Increased permeability to water.

• Smaller volume of more concentrated urine.

• Travels through bloodstream to kidney tubules.

• Pituitary gland releases ADH into the pancreas.