Skin and Tissue

Question 1

what is keratinisation

Answer 1

organic process by keratin is deposited in cells and these become horny as in dead skin, nails and hair

Question 2

what are the 2 layers of the dermis

Answer 2

papillary layer

reticular layer

Question 3

what is the papillary layer

Answer 3

1st layer of dermis
loose connective tissue
cellular
protective against pathogens

Question 4

what is the reticular layer

Answer 4

dense irregular connective tissue
fibrous
collagen bundles in 3 planes
elastic fibres

Question 5

what tissues does skin consist of

Answer 5

epithelium
connective
muscle
nerve

Question 6

what are epidermal cells termed

Answer 6

keratinocytes

Question 7

whats the function of the dermis

Answer 7

maintains epidermis w blood flow
body cooling
uv protection
immune surveillance

Question 8

What’s the hypodermis?

Answer 8

adipose (fatty) layer beneath skin

subcutaneous tissue, anchors skin to underlying structures

Question 9

what is the epithelial

Answer 9

The tissue covering and protects the body surface and internal organs
stratified squamous keratinising epithelium

Question 10

what are the 4 types of epidermal cells

Answer 10

keratinocytes, melanocytes, langerhans cells, merkel cells

Question 11

What are keratinocytes?

Answer 11

epidermal cells, contain keratin, resistant to abrasion, extrude lipids
constantly dividing, self regeneration protect from trauma

Question 12

what are melanocytes

Answer 12

epidermal cells, pigment formation

Question 13

What are Langerhans cells?

Answer 13

Specialised dendritic cells found in the skin

immune surveillance

Question 14

What are Merkel cells?

Answer 14

touch receptors

Question 15

what are the epidermal layers

Answer 15

(superficial) stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale

Question 16

Where does skin colour come from and what layer of the epidermis is it in?

Answer 16

melanin - protects agaisnt UV
melanocytes
in stratum. germinativum

Question 17

explain hair

Answer 17

it is NOT thermoregulatory in humans
practical use in skin repair
from epithelial layer

Question 18

explain the origin of hair follicles

Answer 18

from epidermis in utero 
downgrowth of epithelial cells 
invasion of knot of blood vessels
growth of hair
continuity with layers of epidermis

Question 19

describe hair follicle structure

Answer 19

hair + sheath
- arrector pilli muscles: attached to follicle root and base epidermis
follicle at angle
hair straightens when muscle contracts

• sebaceous glands: between follicle and arrector pilli muscle
  secretes sebum
  in DERMIS

Question 20

explain nails

Answer 20

strong plate of hard keratin , grows out of nail bed
nail plate analogous to stratum corneum
eponychium
hyponchium

Question 21

what is the eponychium and its function

Answer 21

cuticle, thickened layer of skin around nail

protect skin from exposure to bacteria

Question 22

what is the hyponchium

Answer 22

thickened portion of epithelium underlying free edge of the nail plate on the nail

Question 23

what are the type of skin glands

Answer 23

sebaceous - hair + sebum

2 types of sweat glands

• eccrine (everywhere)
• apocrine (pubic areas, arm pit)

all in dermis

Question 24

explain eccrine sweat glands

Answer 24

simple tubular glands
in dermis 
coiled secretory portion 
coiled and straight ducts in dermis 
spiral channels in epidermis

Question 25

how does thermoregulation happen in the skin

Answer 25

through sweat glands + | blood vessel dilation (absorption and radiation)

Question 26

what are the sensory nerve ending in the skin

Answer 26

meissner's corpuscles - light touch, fingertips paccinian corpuscles - vibration and pressure pain receptors thermoreceptors

Question 27

what are the 4 types of tissue

Answer 27

epithelium connective muscle nerve

Question 28

whats the function of the epidermis

Answer 28

covers surfaces cells connected separates compartments forms glands

Question 29

what are examples of connective tissue

Answer 29

blood, bone, adipose tissue

Question 30

describe muscle tissue and 3 types

Answer 30

contractile long thin cells skeletal, cardiac and smooth

Question 31

describe skeletal muscle

Answer 31

striated, highly ordered

Question 32

describe cardiac muscle

Answer 32

striated, branched

Question 33

describe smooth muscle

Answer 33

non-striated randomly ordered. one nucleus per cell

Question 34

function of nervous tissue?

Answer 34

communication | receives, generates and transmits electrical signals.

Question 35

describe neurone structure

Answer 35

cell body (soma) dendrites axon terminals

Question 36

how does epithelial tissue connect cells

Answer 36

no contact inhibition cell - cell junctions cell - ECM junctions

Question 37

what are desmosomes

Answer 37

``` adhering junctions function - firm anchorage ```

Question 38

what are tight junctions

Answer 38

occluding junctions | - seals intercellular spaces

Question 39

what are gap junctions

Answer 39

communicating junctions | cell - cell communication

Question 40

what is the basement membrane and what does it consist of

Answer 40

layer of proteins, separates epithelium from lamina propia | made up of basal lamina and reticular lamina

Question 41

what are some cell-ecm junctions

Answer 41

hemidesmosomes

Question 42

what is cilia

Answer 42

epithelium secondary roles - movement

Question 43

what is microvilli

Answer 43

epithelium secondary roles -- absorption

Question 44

whats the difference between simple and stratified epithelium

Answer 44

simple - one cell thick | stratified - more than 1 layer

Question 45

what are the types of epithelium structure

Answer 45

squamous, cuboidal and columnar

Question 46

what are glands

Answer 46

collections of secretory epithelial cells single or multicellular exocrine or endocrine

Question 47

What are endocrine glands

Answer 47

secrete into blood

Question 48

what are exocrine glands

Answer 48

secrete into tubes

Question 49

what types of exocrine glands to you get

Answer 49

simple - tubular and acinar compound - tubuloacinar mucous and serous glands

Question 50

what r mucous glands

Answer 50

secretion rich in proteoglycans | secretion + water = mucus

Question 51

what are serous glands

Answer 51

watery, enzymes | protein rich secretion

Question 52

what are the methods of exocrine secretion

Answer 52

- diffuse through cells - pinched off portion of cell - disintegrating cell and its contents

Question 53

what are myoepithelial cells

Answer 53

they expel the secretions of exocrine glands

Question 54

what is the pituitary gland

Answer 54

secretes growth hormone | can over produce and under produce

Question 55

where is adipose tissue found

Answer 55

in bone marrow + mesenteric fat around intestines

Question 56

what fibres are there in the ECM in connective tissue

Answer 56

collagen and elastin

Question 57

what are the types of collagen

Answer 57

Type 1 - tendons type 3 - reticulin type 4 - in basal lamina

Question 58

explain elastic fibres

Answer 58

``` protein elastin stretch 1.5 times resting length microfibrils and amorphous component found in sheets yellow colour (aorta) ```

Question 59

what are the components of the ECM in connective tissue

Answer 59

fibres ground substance - like jelly tissue fluid

Question 60

whats in the ground substance

Answer 60

semi-solid gel proteoglycans hyaluronic acid glycoproteins

Question 61

what types of connective tissue are there

Answer 61

loose dense regular dense irregular

Question 62

describe loose connective tissue

Answer 62

``` permanent (fixed) cells fibroblasts macrophages adipcytes mast cells ``` transient cells - wbc

Question 63

what are the layers of the skin

Answer 63

epidermis and dermis

Question 64

whats the function of the epidermis

Answer 64

prevents water loss by evaporation