Basics

Question 1

Function of skin

Answer 1

1. protection from environment
2. containment for body’s structures and vital substances
3. heat regulation by evaporation of sweat and constriction/dilation of superficial blood vessels
4. sensation using superficial nerves
5. synthesis of vitamin D

Question 2

Epidermis

Answer 2

superficial layer that provides protection; has no blood vessels –> nourished by dermis which is vascularized

Question 3

Dermis

Answer 3

made of deep connective tissue of interlacing collagen and elastic fibres; supplied by arteries and afferent nerve endings

Question 4

Layer of skin responsible for sensation

Answer 4

dermis because it contains the afferent nerve endings

Question 5

Hair follicles

Answer 5

found in deep layer of dermis

Question 6

Arrector muscles of hairs

Answer 6

small muscles around hair follicles that contract to cause hair to stand up; contraction also allows for secretion of oil from sebaceous glands

Question 7

Sebaceous glands

Answer 7

secrete oil, exocrine gland that lies on the side of hair follicle

Question 8

Skin ligaments

Answer 8

small fibrous bands that connect deep surface of dermis to deep fascia underneath; longer ligaments mean more mobile skin

Question 9

Subcutaneous tissue

Answer 9

superficial fascia lying superficial to deep fascia, composed mainly of connective tissue and stores fat; contains sweat glands, superficial blood vessels, lymphatic vessels, and nerves

Question 10

Structures of skin involved in heat regulation

Answer 10

blood vessels constrict or dilate; sweat glands release water that evaporates to remove heat; arrector muscles contract to raise hair up which traps warm air close to body

Question 11

Structures of skin involved in protection

Answer 11

epidermis; sebaceous glands secreting sebum

Question 12

Structures of skin involved in sensing

Answer 12

superficial nerves in dermis

Question 13

Langer’s lines

Answer 13

lines corresponding to the natural orientation of collagen fibres in the dermis

Question 14

Epithelia

Answer 14

cells that cover or line all body surfaces, tubes and cavities

Question 15

Function of epithelia

Answer 15

form interfaces between different fluid compartments

Question 16

How epithelial cells are held together

Answer 16

tight junctions

Question 17

Basement membrane

Answer 17

separates epithelial cells from underlying tissues; composed of two layers –> basal lamina and reticular connective tissue

Question 18

Basal lamina

Answer 18

thin proteoglycan layer laid down by epithelial cells; part of basement membrane

Question 19

Reticular connective tissue

Answer 19

bed for epithelial cells to anchor to; part of basement membrane

Question 20

Carcinoma

Answer 20

cancer in the epithelial cells caused in part by rapid division of ep. cells to replace those that have desquamated

Question 21

Characteristics of epithelia

Answer 21

cells packed together with high cell density, basement membrane underneath which orients cells

Question 22

Simple epithelia

Answer 22

one layer of epithelial cells; all cells directly attached to BM

Question 23

Where is simple epithelia found?

Answer 23

sites in body where quick diffusion or absorption is needed:

• lungs
• digestive system

Question 24

Stratified epithelia

Answer 24

multiple layers of epithelial cells, creating basal and apical cells

Question 25

Basal cells

Answer 25

cells in stratified epithelia that are in contact with BM

Question 26

Apical cells

Answer 26

cells in stratified epithelia that are in contact with lumen

Question 27

Where is stratified epithelia found?

Answer 27

sites in body where there is a need for protection from friction, trauma, or caustic content - stomach - bladder

Question 28

Epithelial cell shapes

Answer 28

squamous, columnar, cuboidal