Get premium membership and access questions with answers, video lessons as well as revision papers.
Epidermis
it is made up of three layers
the outermost layer, comi?ed layer is made up of dead cells that prevent entry of microorganisms, prevent physical damage and dessication
granular layer made of living cells gives rise to corni?ed layer
malpighian layer is made up of actively dividing cells that give rise to new epidermal cells/granular layer it contains melanin that protects the body against ultra violet rays(radiations)
Dermis
has several components
Has sweat gland which produce sweat through sweat pores on the skin and the sweat evaporates cooling the body by lowering body temperature. When it is cold, no sweat is produced, conserving water
sweat contains water, sodium chloride, uric acid and urea hence the skin acts as an excretory organ
Has hair. The hair stands erect to trap air when temperature is low to reduce loss/insulation. It lies ?at to allow heat loss when temperature is high.
Has nerve endings which are sensitive to stimuli such as heat, cold, pain, pressure and touch
Has subcutaneous fat/adipose fat that insulates the body against heat loss
Has arteries and capillaries (blood vessels) that supply food and oxygen and remove excretory products. Arterioles vasodilate when temperatures are high to lose heat by radiation, and convention. Arterioles constrict when temperatures are low to conserve heat i.e. reduce heat loss
Has sebaceous glands which secrete sebum, and antiseptic and water repellant that prevents drying and cracking the skin by making the skin supple
Mohaissack answered the question on October 5, 2017 at 14:14
- List excretory organs and products of mammals(Solved)
List excretory organs and products of mammals
Date posted: October 5, 2017. Answers (1)
- Describe excretion in unicellular organisms(Solved)
Describe excretion in unicellular organisms
Date posted: October 5, 2017. Answers (1)
- State the excretory products of plants and some of their uses to humans(Solved)
State the excretory products of plants and some of their uses to humans
Date posted: October 5, 2017. Answers (1)
- Why do plants lack complex excretory structures like those of animals?(Solved)
Why do plants lack complex excretory structures like those of animals?
Date posted: October 5, 2017. Answers (1)
- Describe how excretion takes place in green plants(Solved)
Describe how excretion takes place in green plants
Date posted: October 5, 2017. Answers (1)
- (a)What is the function of the objective lens in a light microscope? (b)Give one advantage of using a light microscope over that of electron microscope.(Solved)
(a) What is the function of the objective lens in a light microscope?
(b) Give one advantage of using a light microscope over that of electron microscope
Date posted: October 5, 2017. Answers (1)
- Explain why excretion is necessary in plants and animals(Solved)
Explain why excretion is necessary in plants and animals
Date posted: October 5, 2017. Answers (1)
- Define the following terms: (i) Excretion (ii)Secretion (iii) Egestion (iv)Homeostasis(Solved)
Define the following terms
(i)Excretion
(ii)Secretion
(iii)Egestion
(iv)Homeostasis
Date posted: October 5, 2017. Answers (1)
- Mention the types of experiments carried out for respiration(Solved)
Mention the types of experiments carried out for respiration
Date posted: October 5, 2017. Answers (1)
- Explain the disadvantages of anaerobic respiration(Solved)
Explain the disadvantages of anaerobic respiration
Date posted: October 5, 2017. Answers (1)
- Why does anaerobic respiration of a given substrate yield a smaller amount of energy than aerobic respiration?(Solved)
Why does anaerobic respiration of a given substrate yield a smaller amount of energy than aerobic respiration?
Date posted: October 5, 2017. Answers (1)
- State functions of DNA molecule(Solved)
State functions of DNA molucule
Date posted: October 5, 2017. Answers (1)
- What is respiratory quotient(RQ)?(Solved)
What is respiratory quotient(RQ)?
Date posted: October 5, 2017. Answers (1)
- State the economic importance of anaerobic respiration(Solved)
State the economic importance of anaerobic respiration
Date posted: October 5, 2017. Answers (1)
- How does movement in plants differ from that of animals?(Solved)
How does movement in plants differ from that of animals?
Date posted: October 5, 2017. Answers (1)
- Why does lactic acid level reduce after exercise?(Solved)
Why does lactic acid level reduce after exercise?
Date posted: October 5, 2017. Answers (1)
- Why is there a high rate of lactic acid production during exercise?(Solved)
Why is there a high rate of lactic acid production during exercise?
Date posted: October 5, 2017. Answers (1)
- Give a word equation of anaerobic respiration in animals(Solved)
Give a word equation of anaerobic respiration in animals
Date posted: October 5, 2017. Answers (1)
- State the word equation representing anaerobic respiration in plants(Solved)
State the word equation representing anaerobic respiration in plants
Date posted: October 5, 2017. Answers (1)
- What are the end products of aerobic respiration?(Solved)
What are the end products of aerobic respiration?
Date posted: October 5, 2017. Answers (1)