Week 3 Flashcards
(111 cards)
1
Q
Simple
A
one layer of cells
2
Q
Stratified
A
two or more stacked layers of cell
3
Q
Pseudostratified
A
appears layered but isn’t - found in the respiratory tract
4
Q
Squamous cells
A
flat, thin and scale-like
5
Q
Cuboidal cells
A
cube-shaped (box-like) with centrally located nucleus
6
Q
Columnar cells
A
tall and rectangular-shaped, with nuclei usually near the base
7
Q
Two forms of epithelial tissue
A
- Covering and lining epithelium – forms the outer layer of the skin, dips into and lines the open cavities of the urogenital, digestive and respiratory systems, and covers the walls and organs of the closed ventral body cavity
- Glandular epithelium – surrounds the glands within the body
8
Q
Main 5 characteristics of epithelial tissues
A
Polarity
Specialised contacts
Supported by connective tissue
Avascular
Innervated
9
Q
What is polarity in relation to epithelium?
A
All epithelium has an apical surface and a lower attached basal surface that differ in structure and function
10
Q
What is specialised contacts in relation to epithelium?
A
Epithelial cells fit close together and form a continuous sheet. They do this with tight junctions and desmosomes
11
Q
Why is the epithelium supported by connective tissue?
A
All epithelium are supported by connective tissue. The basement membrane reinforces the epithelium and helps to resist stretching and tearing.
12
Q
Why is the epithelium vascular and inverted?
A
The epithelium is avascular, or contains no blood vessels. It is highly innervated, or supplied by nervous fibres. Epithelium has a high ability to regenerate and can reproduce itself as long as it receives adequate nutrition.
13
Q
Simple squamous epithelium Appearance
A
- Single layer
- Close fitting
- Flattened laterally
14
Q
Simple squamous epithelium Function
A
- Absorption
- Secretion
- Filtration
15
Q
Simple squamous epithelium Location
A
- e.g. Alveoli (lungs), glomeruli (kidneys)
16
Q
Simple cuboidal epithelium appearance
A
- Single layer
- Cuboidal cells
17
Q
Simple cuboidal epithelium function
A
- Absorption
- Secretion
18
Q
Simple cuboidal epithelium location
A
- e.g. Small ducts of glands, kidney tubes
19
Q
Simple columnar epithelium Appearance
A
- Single layer of tall cells
- Closely packed
- Modifications can be found: Microvilli on the surface of absorptive cells; Goblet cells for mucus secretion
20
Q
Simple columnar epithelium Function
A
- Absorption
- Secretion
- Associate with mucus-secreting cells
21
Q
Simple columnar epithelium location
A
- e.g. Digestive tract
22
Q
Pseudostratified columnar epithelium Appearance
A
- Column-shaped cells that vary in height, some tall cells reach free apical surface, and other cells do not
23
Q
Pseudostratified columnar epithelium Function
A
- Secretion
- Propulsion
24
Q
Pseudostratified columnar epithelium Location
A
- e.g. Respiratory tract (trachea)
25
Stratified squamous epithelium Appearance
* Multiple layers of cells
* Apical surface cells = squamous
* Deeper layer cells = cuboidal or columnar
26
Stratified squamous epithelium Function
* Protection
27
Stratified squamous epithelium Location
* e.g. External part of skin
28
Stratified cuboidal epithelium appearance
* Many layers for cuboidal cells
29
Stratified cuboidal epithelium function
* Protection and secretion
30
Stratified cuboidal epithelium location
* e.g. Ducts of glands (sweat glands, mammary glands)
Note: Rare
31
Stratified columnar epithelium appearance
* Many layers of columnar cells
32
Stratified columnar epithelium function
* Protection and secretion
33
Stratified columnar epithelium location
* e.g. Pharynx, urethra, glandular ducts, transition areas or junctions
Note: Rare
34
Transitional epithelium Appearance
* Multiple layers of cells
* Basal layer = cuboidal or columnar. Cells in the apical layer can change their shape
35
Transitional epithelium function
* Forms the lining of hollow urinary bladder which stretches when it fills with urine
36
Transitional epithelium Location
* e.g. Lining of hollow urinary organs
37
What is a gland?
One or more cells that produce and secrete a specific product. The product is always a water-based fluid and usually contains proteins.
38
What are the two sets of traits of glands?
Endocrine
(Internally secreting)
Exocrine
(Externally secreting)
Unicellular glands
(One cell type)
Multicellular glands
(More than one cell type)
39
Endocrine glands
Also called ductless glands because eventually they lose their ducts. They produce hormones, or chemical messengers, and secrete them by exocytosis into the extracellular space. After entering the extracellular space, they enter the blood or lymphatic fluid and travel to specific organs.
40
Exocrine glands
Secrete their products onto the skin or into body cavities. Unicellular exocrine glands do this directly by exocytosis, while multicellular glands transport their products through a duct onto the epithelial surface. Products secreted by exocrine glands include sweat, oil, mucus, bile and more. Unicellular exocrine glands include goblet cells and mucus-secreting cells. They can be found within epithelial linings of the intestinal and respiratory tracts. Multicellular exocrine glands have two main parts, an epithelium derived duct and a secretory unit made up of secretory cells. Multicellular exocrine glands are structurally classified depending on the structure of their ducts and can be classified as either simple glands, where they are unbranched, or compound glands, where they have multiple branched ducts. Their glands can be further categorised by the secretory units: tubular if the secretory cells form tubes, alveolar if the secretory cells form small sacs, or a combination of any of these.
41
Main classes of connective tissue
connective tissue proper (which includes fat and the fibrous tissue of ligaments)
cartilage
bone
blood
42
Types of connective tissue proper
loose connective tissue
dense connective tissue
43
Types of loose connective tissue
areolar
adipose
reticular
44
Types of dense connective tissue
dense regular
dense irregular
elastic
45
Types of cartilage
hyaline cartilage
elastic cartilage
fibrocartilage
46
areolar connective tissue function
supporting and binding other tissues
defending against infection
holding body fluids
storing nutrients
47
areolar connective tissue appearance
most widely distributed
fibroblast
loose arrangement of fibres
lots of ground substance
48
Connective tissue important functions
1. binding and supporting
2. protecting
3. insulating
4. storing reserve fuel
5. transporting substances within the body.
49
Types of muscle tissue
1. Skeletal muscle that attach to bones to enable us to produce voluntary movement.
2. Smooth muscle that line hollow organs to help squeeze substances through these organs.
3. Cardiac muscle in the walls of the heart to propel blood through blood vessels to other paths of the body.
50
Muscle tissue
Distinguishable from other tissue types by its ability to transform chemical energy (ATP) into directed mechanical energy to produce movement.
All possess contractile filament networks (made up of actin and myosin proteins) that bring about movement and contraction.
The function of muscle tissue varies with its location in the body.
51
Types of tissues/cells
Nervous
Muscle
Epithelial
Connective
52
Main components of connective tissue
1. ground substance
2. fibres
3. cells
53
What is ground substance?
A clear, colourless viscous fluid that fills the space between the cells and fibres
54
Types of fibres
Collagen
Elastic
Reticular
55
What is collagen?
Fibrous protein that is extremely tough and provide high tensile strength
56
What is elastic?
Elastin that stretches and recoils like rubber bands
57
What is reticular?
Reticular fibres are short, fine collagenous fibres that branch extensively to form a delicate network.
58
-blast meaning
immature
59
fibroblast function
actively proliferating and secrete the ground substance and the fibres characteristic of their particular matrix
60
-cyte meaning
mature
61
-cyte function
maintain health of the matrix
can revert to their active, immature, state to repair and regenerate the matrix
62
Fat cells function
store nutrients
63
White blood cells function
neutrophils, eosinophils, lymphocytes involved in immune response
64
Mast cells function
typically cluster along blood vessels, detect and remove foreign microorganisms and initiate local inflammation
65
macrophages function
type of white blood cell that cleans the body of unwanted microscopic particles, such as bacteria and dead cells
66
adipose (fat) tissue function
store energy (lipids)
cushions and insulates the body
67
adipose (fat) tissue appearance
sparse
closely packed adipocytes (fat cells)
68
reticular connective tissue function
internal frameworks that can support immune cells
69
reticular connective tissue appearance
delicate network of reticular fibres
70
dense regular connective tissue function
* tendons that attach to muscles to bone
* sheet like tendons that attach muscles to other muscles or to bones
* ligaments that bind together at the joints
* fascia, a fibrous membrane, that wraps around the muscles, blood vessels and nerves
71
dense regular connective tissue appearance
* closely packed bundles of collagen fibres running in the same direction
* slightly wavy
* fibroblasts
72
dense irregular connective tissue function
* found in areas where tension is exerted from many different directions
* part of the skin dermis area
* in the fibrous joint capsules of the limbs
* the fibrous covering that surrounds some organs
73
dense irregular connective tissue appearance
* same structural elements as dense regular tissue but the bundles of collagen fibres are much thicker and arranged irregularly
74
elastic connective tissue function
* allow the tissues to recoil after stretching
* around vertebrate
* blood vessel walls
* bronchial tubes
75
elastic connective tissue appearance
similar to dense regular connective tissue with more elastic fibres
76
hyaline cartilage function
provides strong support while providing pads for shock absorption
77
hyaline cartilage appearance
* large number of collagen fibres, its matrix appears transparent or glassy
* chondrocytes
78
elastic cartilage function
* maintain the shape of the structure while allowing flexibility
* skeleton of the external ear and in the epiglottis
79
elastic cartilage appearance
* similar to hyaline cartilage but has many more elastic fibres
* chondrocytes
80
fibrocartilage function
* compressible and resists tension
* found in the intervertebral disks of the bony vertebrae and knee meniscus
81
fibrocartilage appearance
rows of chondrocytes alternating with rows of thick collagen fibres
82
bone (osseous tissue) function
* supports and protects body structures
* stores calcium and other materials and fat
* marrows inside bone site for synthesising blood cells
83
bone (osseous tissue) appearance
* hard, calcified matrix containing many collagen fibres
* osteocytes, reside in lacunae
* osteons formed of concentric rings of bony matrix (lamellae) surrounding central canals containing the blood vessels and nerves
84
blood function
delivers necessary substances, such as nutrients and oxygen, to the cells and transports metabolic waste products away from those same cells
85
blood appearance
red and white blood cells surrounded by a non-living fluid called plasma
86
cardiac muscle function
found only in myocardium, contracts in response to signals from the cardiac conduction system to make the heart beat and propel blood around the body
87
cardiac muscle appearance
branching, striated, generally uninucleate cells that connect at specialised junctions called intercalated discs
88
skeletal muscle function
attach to and move bones by contracting and relaxing in response to voluntary messages from the nervous system
89
skeletal muscle appearance
long, cylindrical, multinucleate cells, striated appearance
90
smooth muscle function
changes shape to facilitate bodily functions
propels substances (food stuff, urine or baby) or objects along internal passageways
involuntary
91
smooth muscle appearance
spindle-shaped cells with central nuclei, no striations, cells arranged closely to form cells
92
What is nervous tissue?
The main component of the nervous system (brain, spinal cord and nerves) and is made up of neurons and supporting (glial) cells. This tissue transmits messages (electrical impulses) over long distances within the body to allow us to respond to stimuli, perceive sensations and control muscles.
93
Where is nervous tissue found?
central nervous system and peripheral nervous system
brain, spinal cord and nerves
94
nervous tissue function
regulates and controls body function
95
What are neurons and what is their function?
basic unit of nervous tissue that sense stimuli and transmit nerve impulses around the body
96
Function of neuroglial cells
various functions in support of nerve cells
97
what is the cell body?
central cell body contains the neuron's nucleus and other organelles
98
what are nerve processes?
projections from the cell body that are able to conduct and transmit signals
99
What do axons do?
carry signals away from the cell body
100
what do dendrites do?
carry signals toward the cell body
101
glial cells function
* support nervous system
* astrocytes form blood brain barrier
* oligodendrocytes (schwann cells) form myelin sheath around nerve axon
* supply of nutrients to neurons
* removes excess neurotransmitters
* maintains electrolyte balance
* nervous system repair
* protection against microorganisms
102
What is regeneration?
proliferation of cells and tissue. complete restoration of lost tissue structures.
103
What is repair?
proliferation of cells and tissue and scar formation. tissue structure will not be restored.
104
What is regeneration capacity?
Varies widely from one tissue to another
105
Tissues that regenerate extremely well
e.g. epithelial tissue, bone, dense irregular connective tissue, blood-forming tissue
106
Tissues with moderate regenerative capacity
e.g. smooth muscle and dense regular connective tissue
107
Tissues with weak regenerative capacity
e.g. skeletal muscle and cartilage
108
Tissues that lose their ability to divide after early development and virtually have no functional regenerative capacity -- routinely replaced by scar tissue
e.g. nervous tissue and cardiac muscle
109
What do stem cells do?
mediate regeneration
provide new cells for body as it grows and replace specialised cells that are lost or damaged
110
Stem cells two unique properties
1. Can divide over and over to produce new cells
2. Can change into other cells that make up the body as they divide
111
vascularisation
blood supply
low vascularisation = tissue heals slowly
