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Flashcards in Integument Deck (46):
0

What cells of the epidermis are responsible for producing pigment and colouration?
Which layer of the epidermis are they found?

Melanocytes
St Basale

1

What is the main cell type in the epidermal layers?

Keratinocytes

2

What is the name of the muscle which causes hair to become erect?

Erector pili

3

What are the two types of sweat glands?

Apocrine and eccrine

4

Which type of sweat gland is found in the footpad?

Eccrine

5

What epithelium does the epidermis consist of?

Keratinised stratified squamous

6

What do sudoriferous glands secrete?

Sweat

7

Which cells are present in the outer cuticle of the hair shaft?

Flat keratinised cells

8

Which cells are present in the cortex of the hair shaft?

Dead cell layer

9

What cells are present in the medulla of a hair shaft?

Cuboidal or flat cells

10

What do sebaceous (oil) glands secrete?

Sebum

11

What are the functions of sebum?

Retards water loss
Lubricates skin
Inhibits growth of certain bacteria
Helps spread sweat
Territorial marker

12

How do androgens affect sebum secretion?

Increase it

13

How does oestrogen affect sebum secretion?

Decrease it

14

What are the names of the two melanin pigments?

Eumelanins (black and brown colouration)
Pheomelanins (red and yellow colouration)

15

Give an example of soft keratin

Skin

16

Give an example of hard keratin

Nails, horn, hoof

17

What are the three receptor types in skin?

Mechanoreceptors (touch and pressure)
Thermoreceptors (temperature)
Nociceptors (intense stimuli-pain_

18

Which nervous system controls blood flow to the skin?

Sympathetic

19

What is the difference between panting and sweating, in terms of what is lost from the body?

Sweating - loss of water and NaCl
Panting - loss of water

20

What does the epidermis originate from?

Ectoderm

21

What does the dermis originate from?

Mesoderm

22

Thickness of skin refers to relative thickness of which layer?

Epidermis

23

What are the 5 layers of the epidermis?

St Corneum
St Lucidum
St Granulosum
St Spinosum
St Basale

24

What processes occur in the epidermis?

Continuous proliferation of keratinocytes in basal layer
Migration, differentiation and keratinisation of keratinocytes
Squamous cells sloughed off at surface

25

How does the epidermis receive blood supply?

Nourished by diffusion from blood vessels in dermis

26

How does the dermis receive blood supply?

Contains blood vessels, lymphatic vessels, nerves, arteriovenous anastomoses

27

What is contained in the hypodermis?

Loose and irregular connective tissue
Large deposits of fat

28

What are the functions of hairs?

Mechanical protection
Thermoregulation
Sensory perception

29

What epithelium covers the hair bulb?

Stratified squamous

30

Describe the cyclic activity of a hair

Anagen phase-growth
Catagen-hair atrophies
Telogen-hair is displaced distally and new hair matrix begins to form
Anagen-new hair matrix is established, renewed growth

31

Which specialised glands are present in pigs?

Preputial-opening of foreskin
Sexual attraction, initiates mating behaviour in sows

32

Which specialised glands are present in sheep?

Infraorbital pouch-territorial marking
Interdigital glands-produces a fatty secretion, marking of footprints to signal to others in flock

33

Which specialised glands are present in dogs?

Anal glands-release a fatty secretion during defaection, territorial marking
Tail gland-oval patch on dorsal tail, territorial marking, skin has sparser hair

34

How does melanin protect against sun damage?

Melanin is able to absorb UV radiation, protecting cells from UVB radiation damage

35

Where is MSH secreted?

Pituitary gland

36

If MSH receptors are not stimulated, what colour pigments are produced?

Red/yellow pheomelanins

37

Melanin pigments are a derivative of which amino acid?

Tyrosine

38

What causes the epidermis to be impermeable to water?

Stratum corneum and granular cell layer
Sebaceous gland secretion contributes to water resistance
Keratinocytes contain insoluble keratin and synthesise lipids

39

What makes hard keratin harder than soft keratin?

Contains more sulfar, less elastic, resistant to degradation

40

What is photosensitivity?

Abnormal reaction to sunlight due to accumulation of photosensitive compounds below the skin

41

Which are the two types of tonic, slow-adapting sensory cells?

Merkel cell and Ruffini corpuscle
Both located near skin's surface, sensitive to touch, pressure and duration

42

Which are the two types of phasic, fast-adapting sensory cells?

Meissner corpuscle-phasic receptor sensitive to fine touch, concentrated in hairless skin
Pacinian corpuscle-pressure-sensitive phasic receptor deep below skin in subcutaneous tissue

43

How do tonic receptors differ from phasic receptors?

Tonic receptors are slowly adapting, but respond for the duration of a stimulus. Fire rapidly when first activated then become slower. eg baroreceptors.
Phasic receptors are fast adapting. They rapidly adapt to a constant stimulus then turn off.

44

How does the brain locate and detect intensity of a stimulus?

Frequency of action potentials
Number of receptors stimulated
Different receptors have different thresholds

45

Which nervous system contracts the erector pili muscle?

Sympathetic