Skin and tissues Flashcards
1
Q
What are the 2 layers found in the skin?
A
Dermis and epidermis
2
Q
What is the function of the epidermis?
A
Forms boundary between internal and external environments
3
Q
What type of tissue is the epidermis?
A
Epithelial tissue
4
Q
What is the function of the dermis
A
Supports and protects the skin and deeper layers, assists in thermoregulation and aids in sensation
5
Q
What type of tissue is the dermis?
A
Connective tissue
6
Q
Under the dermis lies what?
A
Hypodermis(adipose tissue under the skin, not part of the skin, it anchors skin to underlying structures)
7
Q
What are the 4 types of epidermal cells?
A
keratinocytes
Melanocytes
Langerhangs cells
Merkel cells
8
Q
What is the function of keratinocytes?
A
Extrude lipids making them water proof. They constantly self divide and regenerate, protecting them from trauma. (most common epidermal cell)
9
Q
What is the function of melanocytes?
A
Responsible for pigment formation
10
Q
What is the function of langerhans cells?
A
Responsible for immune surveillance
11
Q
What is the function of merkel cells?
A
Touch receptors
12
Q
Identify the cell type represented by A
A
Keratinocytes
13
Q
Identify the skin cell type represented by B
A
Melanocyte
14
Q
Identify the cell type represented by C
A
Langerhans cells
15
Q
What are the layers of the epidermus?
A
Stratum basale
Stratum spinosum
stratum granulousum
stratum lucidum
stratum corneum
16
Q
Does the epidermis have any blood vessels?
A
Nope
17
Q
What is the function of the stratum basale
A
The cells in the stratum basale bond to the dermis via intertwining collagen fibres reffered to as the basement membrane. All of the karatinocytes are produced from this single layer of cells. As new cells are formed, the exisitng cells are pushed superficially away from the statum basale
18
Q
What is a basale cell?
A
A cuboidal shaped stem cell that is a precursor of all the keratinocytes of the epidermis
19
Q
What type layer is represented by A
A
Stratum corneum
20
Q
What layer of the skin is represented by B
A
Stratum lucidum
21
Q
What layer of the skin is represented by C
A
Stratum granulousum
22
Q
What layer of the epidermis is represented by D?
A
Stratum spinosum
23
Q
What layer of the epidermis is represented by E?
A
Stratum basale
24
Q
Where does keratinisation begin?
A
Stratum spinosum
25
What occurs within the statum corneum?
This is where the converstion of keratohyalin to keratin takes place
26
How long does keratinisation take?
15-30 days
27
What is keratin?
An intracellular fibrous protein that gives hair, nails and skin their hardness and water-resistant properties
28
What structures are located within the dermis?
Blood and lymph vessels. nerves and other folliceles such as sweat glands
29
What aer the 2 layers located within the dermis?
Papillary layer and reticular layer
30
What is the papillary layer?
A superficial layer of dermis that projects into the strtum basale of the epudermis to form finger like dermal papilla (plural=dermal papillae)
31
What is the function of dermal papillae
They increase the strength of the connection between the epidermis and the dermis - the greater the folding, the stronger the connections made
32
What type of tissue is the papillary layer?
Loose connective tissue
33
What type of tissue is the reticular layer?
Irregular connective tissue
34
What is the function of the reticular layer?
The treticular layer appears reticulated (net-like) due to a tight meshwork of fibres. Elastin fibres provide some elasticity to the skin, enabling movement.
Collagen fibres provide strcture and tensile strength, with strands of collagen extending into both the papillary layer and the hypodermis
35
Name 3 pigments which influence the colour of skin
Melanin, carotene and haemoglobin
36
Melanin is produced by what type of cell?
Melanocytes
37
Where are melanocytes found?
Scattered throughout the stratum basale of the epidermis
38
What cellular organelle transferes melanin into the keratinocytes?
Melanosome
39
What aer the two types of skin receptors?
Meissner's corpuscles
Paccinian corpuscles
40
What is the function of meissner's corpuscles?
To sense light touch
41
Where are meissner's corpuscle's found?
Fingertips
42
What do paccinian corpuscles sense?
Vibration and pressure
43
What is the function of arrector pili muscles?
To straighten hair (happen's during contraction)
44
What are arrector pili muscles attached to?
Follicle root and base epidermis
45
Where is the sebaceous gland found?
Between follicle and arrector pili muscle
46
What do sebaceous glands do?
Secretes sebum
Function unknown
47
What are the 4 types of tissue?
Epithelial
Muscle
Nervous
Connective
48
What are the overarching classes of epithelial tissue?
Stratified and simple
49
What is the difference between stratified and simple epithelial tissue?
Simple tissue is one layer thick while stratified tissue is multi-layered§
50
What are the 3 different types of epithelial tissue?
Squamous
Cuboidal
Columnar
51
What are teh 3 types of musclar tissue?
Skeletal muscle
Cardiac muscle
Smooth muscle
52
Where is nervous tissue found?
In the brain, spinal cord and nerves
53
What are the 4 regions of nervous tissue?
(structure of neuron)
Dentrites
Cell body(soma)
Axon
Terminals
54
What are the 5 types of connective tissue
Bone
Blood
Cartialage
Loose connective tissue
Dense connective tissue
55
What is the function of bone?
Provides protection to internal organs and supports the body. Bone's rigid extracellular matrix conatins mostly collagen fibres embedded in a mineralised ground substance containing hydroxyapatite (a form of calcium phosphate)
56
What are the 2 components of blood?
Cells and fluid matrix
57
What are the 3 types of loose connective tissue?
Adipose
Aerolar
Reticular
58
Where is loose connective tissue found?
Between many organs where it acts both to absord shock and bind tissues together
59
What is the function of loose connective tissue?
To diffuse through adjacent or imbedded cells and tissues
60
Describe adipose tissue
This is a loose connective tissue that consists of fat cells with little extracellular matrix. It stores fat for energy and provides insulation
61
Describe areolar tissue
Fills the spaces between muscle fibres, surrounds lymph vessels, and supports organs in the abdominal cavity. Areolar tissue underlies most epithelia and respresents a connective tissue component of epithelial membranes
62
Describe reticular loose connective tissue
Mesh like supportive framework for soft organs such as lymphatic tissue, the spleen and the liver. Reticular cells produce the reticular fibres that form the network onto which other cells attach
63
What are the 3 types of dense connective tissue?
Regular
Irregular
Elastic
64
Describe dense regular connective tissue and state where it is found
Dense regular connective tissue fibres are parallel to each other, enhancing tensile strength and resistance to stretching in the direction of the fibre oreintations
Ligaments and tendons are made of dense regular connective tissue
65
Describe dense irregular connective tissue and state where it is found
In dense irregular connective tissue, the direction of fibers is random. This arrangement gives tissue greater strength in all directions and less strength in one particular direction
Dense irregular connective tissue is found in the lower layers of the skin(dermis) and in the protective white layer of the eyeball
66
Describe elastic connective tissue and state where it is found
Elastic connective tissue is a modified dense connective tissue that conatins numerous elastic fibres in addition to collagen fibres which allows the tissue to return to its original length after stretching
The lungs and areteries have a layer of elastic connective tissue that allows the stretch and recoil of these organs
67
What are the 3 types of cartialage
Hyline
Fibrocartilage
Elastic Cartilage
68
What is cartilage
A tough flexible tissue found throughout the body - it covers the surface of joints, acting as a shock absorber and allowing bones to slide over one another
69
What are chondrocytes and where are they found?
They are essentially cartialage cells, and they are embedded within the cartilage matrix
70
What are lacunae
The space that the chondrocytes occupy in cartialage
71
Describe hyline cartialge and state where it is found
most common type of cartilage in the body. Constists of short and dispered collagen fibres and contains large amounds of proteoglycans. Both strong and flexible it is found in the rib cage and nose and covers bones where they meet to form moveable joints. It makes up a template of the embryonic skeleton before bone formation
72
Describe fibrocartilage and state where it is found
Fibroucartilage is tough because it has thick bundes of collagen fibres dispered through its matrix. The knee and jaw joints and the intervertebral discs are examples of fibrocartilage
73
What are glands?
A collecion of secretory epithelial cells
74
What are the two broad classifications of glands?
Exocine (do have ducts)
Endocrine(do not have ducts)
75
Describe endocrine glands with reference to:
- the presence of ducts
- secretory products
- Route of secretion
- Examples
Endocrine glands do not have ducts. They secrete hormones which are released directly into the bloodstream - eventually reaching the target organ. Examples of endocrine glands incule thyroid glands, adrenal glands and pituitary glands
76
Describe exocrine glands with reference to:
- the presence of ducts
- secretory products
- Route of secretion
- Examples
Exocrine glands have ducts present. They secrete sweat, enzymes, mucus and sebum. These secretory products are released to an internal organ or the external surface through a duct. Examples include salivary glands, pancreas and the liver
77
What are the two classes of shape that exocrine glands can take
Simple or compound
78
What are the two types of simple exocrine shape?
Tubular and acinar
79
What shape is a compound exocrine gland?
Tubuloacinar (combination of tubular and acinar)
80
What are the 3 methods of exocrine secretion?
Merocrine
Apocrine
Holocrine
81
Describe how merocrine glands release secretions
They release their secretions in vesilces, eg salivary glands
82
Describe how apocrine exocrine glands release their secretions
They release their secretions by pinching off a portion of the cell itself, eg mammary gland
83
Describe how holocrine exocrine glands release their secretions
They release their secretions by rupturing the entire cell which contains the product. This is then replaced by cell division. eg some glands in the skin and eyelids
84
What are the 2 main types of fibres found in connective tissue
Collagen and elastin
85
