Human Bio Wk 2

Question 1

The Integumentary System forms a

Answer 1

protective cover over the human body. It has one principle organ, the skin.

Question 2

Functions of the skin include:

Answer 2

protection - protects from water loss and subsequent dehydration of the body.

Question 3

Functions of the skin include:

Answer 3

defence - contains macrophages, called Langerhans Cells/Antigen presenting cells which identify pathogens and phagocytise them.

Question 4

Functions of the skin include:

Answer 4

sensation - the skin contains sense organs for touch, pressure, temperature, pain, itch, tickle.

Question 5

Functions of the skin include:

Answer 5

secretion - the skin secretes the precursor to Vitamin D/ which is then activated in the liver and subsequently in the kidney. In its active state this compound(Vit D) promotes osteogenesis.

Question 6

thermoregulation – Vasodilatation in skin diverts more blood to the skin thus allowing the body to radiate heat. What happens to blood vessels in skin when exposed to cold climate?

Answer 6

Constrict/vasoconstriction

Question 7

The skin is made of two layers

Answer 7

the epidermis is made up of stratified squamous epithelium, and the dermis made of areolar connective tissue.

Question 8

The epidermis is keratinised to help protect it from abrasion and water loss and entry of pathogens in the internal skin

Answer 8

(please remember that the linings of the mouth and vagina are similar to skin except that they are non-keratinised and thus permeable to water, unlike skin).

Question 9

The epidermis is continually replaced by mitosis of the .

Answer 9

germinal cells in the stratum basalae

Question 10

The stratum spinosum or “spiny layer” consists of cells attached to one another which enable the skin to be

Answer 10

pulled and stretched without the cells pulling apart.

Question 11

As the cells push up through these layers they accumulate large amounts of

Answer 11

keratin/keratohyalin/melanin and this substance form the dense granules in the stratum granulosum.

Question 12

Some areas of the skin, notably the palms and soles have an additional layer, the

Answer 12

stratum lucidum or “clear layer” which makes them thicker in order to resist pressure.

Question 13

The outermost layer is called the

Answer 13

stratum corneum because its cells are stiff and horny.

Question 14

The cornified layer will increase in thickness when

Answer 14

subjected to continuous pressure and abrasion. This is what produces the callus seen on the feet and hands.

Question 15

Could you state the functions of the skeletal system?

Answer 15

Support, protection, locomotion, hemopoiesis/haematopoiesis, lipid reserves, mineral stores.

Question 16

Osseous tissue has a matrix containing inorganic salts and collagen fibres. The inorganic matrix gives the rigidity and hardness to bone and is composed of a combination of calcium and phosphorus salts called

Answer 16

hydroxapetite. The collagen fibres give a bone its tensile strength and resistance to stress.

Question 17

Compact bone, made of a dense regular arrangement of osteons is found in the

Answer 17

diaphysis (shaft) of long bones and as the outer layer of all bones.

Question 18

Spongy bone consists of trabeculae (a network) of thin, connecting spicules which form a meshwork in the interior of bones. Spaces between the trabeculae contain

Answer 18

red bone marrow and blood vessels.

Question 19

A fibrous covering of bones which connects to tendons and ligaments is known as the

Answer 19

periosteum.

Question 20

Hormones important to bone growth and homeostasis are

Answer 20

Growth Hormone, Sex hormones, Thyroid Hormone -Calcitonin

Question 21

Osteoporosis is a disorder involving demineralization of bone usually associated with

Answer 21

older individuals can be related to deficiency of calcium, reduced oestrogen levels common in post-menopausal women, reduced activity and exercise.