common integument

Question 1

3 main structures of the integument

Answer 1

1) epidemis
2) dermis
3) subcutis

Question 2

what is subcutaneous tissue

Answer 2

loose connective tissue between the skin and the muscle fascia

Question 3

what does subcutaneous tissue contain

Answer 3

white fat (adipose tissue)

Question 4

what does white fat (adipose tissue) in the subcutaneous tissue

Answer 4

-insulation
-energy source
-padding/protection (eg-footpads)

Question 5

what are cutaneous muscles

Answer 5

thin, interrupted sheets spread over the body in the subcutis

Question 6

name the 6 cutaneous muscles

Answer 6

-platysma (neck and face)
-frontalis (over the frontal bone)
-cutaneous coli (sternum to neck)
-cutaneous trunci (covers side of the trunk)
-cutaneous omobrachalis (continue from trunci over the shoulder and arm)
-preputial muscle (connecting ventral midline to prepuce)

Question 7

which part of the cutis determins the thickness of the skin

Answer 7

dermis

Question 8

what is the dermis made up of

Answer 8

fibrous connective tissue
-collagen fibres (type I, III, V)
-elastin fibres

Question 9

what are the collagen fibres in the dermis known as

Answer 9

Langer lines (or tension lines)

Question 10

what else does the dermis contain

Answer 10

-blood vessels
-nerves
-sensory receptors eg- pacinian corpuscle
-hair follicles
-arector pili muscles
-sebaceous and sweat glands

Question 11

what are the 5 layers of the epidermis (from top to bottom)

Answer 11

-stratum corneum
-stratum lucidum
-stratum granulosum
-stratum spinosum
-stratum basale

Question 12

where are skin cells (keratinocytes) produced

Answer 12

stratum basale

Question 13

how are skin cells (keratinocytes) produced

Answer 13

mitotic cell division

Question 14

movement of skin cells (keratinocytes)

Answer 14

produced in the stratum basalt and then move up the epidermis, differentiating as they go and then eventually slough off (cycle is around 20-30 days)

Question 15

stratum basale

Answer 15

-attachment to dermis
-proliferation of keratinocytes

Question 16

stratum spinosum

Answer 16

-cells closely adhered by desmosomes
-desmosome junctions look spiny under microscope

Question 17

stratum granulosum

Answer 17

-keratinocytes contain densely staining keratohyalin granules
-granules contain products needed for keratinisation (turning keratinocytes to corneocytes)

Question 18

stratum lucidum

Answer 18

-clear layer
-only found in thick, non-hairy skin (eg-footpads)

Question 19

stratum corneum

Answer 19

-thick waterproof cell membrane
-look dead (no organelles or nuclei)
-fewer desmosome attachments so cells can slough off

Question 20

what cells might be found in the epidermis

Answer 20

-melanocytes (pigment cells to protect against sun radiation)
-langerhans cells (immune cells)
-merkel’s cells (touch receptors)

Question 21

7 functions of the common integument

Answer 21

-protection
-immune defence
-sensing evironment
-thermoregulation
-storage and excretion
-communications/ camouflage
-selective permeability

Question 22

protection function of skin

Answer 22

• Physical (e.g.fat, collagen, keratin)
• Radiation (e.g.melanocytes)
• Epidermal organs (horns, claws)

Question 23

immune defence of the skin

Answer 23

• Physical barrier to infection
• Immune cells in skin
• Antimicrobial properties in skin gland secretions

Question 24

sensing environment of the skin

Answer 24

• Pressure receptors
• Pain receptors
• Heat receptors
• Cold receptors
• Tactile hairs
• Toruli tactiles

Question 25

thermoregulation of the skin

Answer 25

* Sweating * Hairs, piloerection and arrector pili * Blood flow to skin * Insulation by fat

Question 26

storage and excretion of the skin

Answer 26

* Fat stores energy, water and vitamins * Glands can excrete water and electrolytes

Question 27

communication and camouflage function of the skin

Answer 27

* Smelly substances from glands * Epidermal organs (e.g. horns) * Raising of hair or feathers (arrector pili) * Pigmentation (melanocytes)

Question 28

selective permeability of skin

Answer 28

* Impermeable to water in mammals (waterproof epidermis, oily secretions from glands) so maintains water balance * Some medications can be absorbed across skin * Some species use skin for respiration

Question 29

3 germ layers in gastrulation

Answer 29

-ectoderm (top) -mesoderm (middle) -endoderm (bottom)

Question 30

what is gastrulation

Answer 30

formation of gastrula and 3 germ layers

Question 31

what is neuralation

Answer 31

formation of neural tissue

Question 32

what does the ectoderm form

Answer 32

epidermal (inc. nails, hair follicles and glands) and neural cells

Question 33

what does the mesoderm form

Answer 33

-dermis and subcutis -musculoskeletal system, connective tissue, organs, blood

Question 34

what does the endoderm form

Answer 34

lining of the gut and respiratory system, and out pouches eg liver and pancreas

Question 35

where do melanocytes come from

Answer 35

neural crest cells (ectoderm)

Question 36

when do somites form

Answer 36

at a later embryonic stage, mesoderm organises itself into blocks of tissue called somites

Question 37

dermatome

Answer 37

segment of dermis derived from one somite, and thus innervated by a single spinal nerve (per body half)

Question 38

somite

Answer 38

embryological precursor to a dermatome

Question 39

pathway of the spinal nerve

Answer 39

after exiting the vertebra it splits into dorsal and ventral branches

Question 40

what do the dorsal branches of the spinal nerve supply

Answer 40

the dorsal cutaneous nerves innervating the dorsal body skin

Question 41

what do the ventral branch of the spinal nerve supply

Answer 41

ventral and lateral cutaneous nerves innervating the ventral and lateral body skin

Question 42

what nerve supplies the limbs

Answer 42

sinal erve