histology Flashcards
(65 cards)
1
Q
what do astrocytes do?
A
- maintain appropriate chemical environment for neuronal signalling
- maintain BBB
- provide nutriments
- remove excess neurotransmitters
2
Q
Where are astrocytes located?
A
CNS
3
Q
What do astrocytes look like?
A
star-like appearance
4
Q
Where are oligodendrocytes located?
A
CNS
5
Q
What do oligodendrocytes do?
A
-lay down laminated, lipid-rich myelin
6
Q
What do Schwann cells do?
A
- lay down laminated, lipid-rich myelin
- participate in regeneration of PNS axons
7
Q
Where are Schwann cells found?
A
PNS
8
Q
What do microglial cells do?
A
- scavenger cells that remove cellular debris from sites of injury (or normal cell turnover)
- secrete signalling molecules (especially range of cytokines that can modulate local inflammation and influence cell survival or death)
9
Q
Where are microglial cells found?
A
CNS
10
Q
What are the properties of neurones?
A
- irritability
- conductivity
11
Q
What are the different types of neurones?
A
- multipolar
- bipolar
- unipolar
12
Q
What are the properties of multipolar neurones?
A
- multiple processes (dendrites/axons)
- motor and sensory neurones
13
Q
What are the properties of bipolar neurones?
A
- 2 processes coming off soma
- find them in the eye, inner ear and roof of nose
14
Q
What are the properties of unipolar neurones?
A
- one process coming off soma
- sensory ganglia in first order neurone (dorsal root ganglion or ganglion cells for CN)
15
Q
(What are ependymal cells?) where are they found? what do they do?
A
- line the ventricles of the brain and central canal of spinal cord
- form cerebrospinal fluid and assist in circulation
16
Q
What are satellite cells?
A
equivalent to astrocytes:
- provide metabolic support for neurone
- remove excess neurotransmitter
17
Q
Where are satellite cells located?
A
in PNS ganglia
18
Q
What is a ganglion?
A
a collection of nerve cell bodies in the PNS
19
Q
What is a nerve?
A
bundle of axons travelling in the PNS
20
Q
What is a nucleus?
A
a collection of nerve cell bodies in the CNS
21
Q
What is a tract/fasciculus?
A
a bundle of axons travelling in the CNS
22
Q
What is a single neurone called?
A
nerve fibre
23
Q
What is the connective tissue layer surrounding a single nerve fibre called?
A
endoneurium
24
Q
What is a fascicle?
A
bundle of nerve fibres
25
What is a the connective tissue layer surrounding the fascicle called?
perineurium
26
What is a nerve?
a group of fascicles
27
What is the connective tissue layer surrounding a nerve?
epineurium
28
What do both cartilage and bone consist of?
- extracellular matrix
- ground substances (elastic and collagen fibres)
- fibroblasts/cytes
29
What are the functions of cartilage?
- framework in respiratory tract
- shock absorption and facilitates joint movement
- covers articular surfaces
- development of long bone
30
What are the properties of cartilage?
firm but flexible, semi rigid
| bears mechanical stress without permanent distortion
31
What does cartilage consist of?
-cartilage cells (CC) (chondrogenic cells and chondrocytes/blasts)
-CC suspended in EMC (extracellular metric)
-cartilage surrounded by perichondrium
(--> cartilage is avascular: receives nutriments from perichondrium)
32
What are the different cartilage cells?
- -> chondrogenic cells:
- differenziate into chondroblasts
- located into the perichondrium
- -> chondroblasts:
- metabolically active young cells
- manufacture matrix
- located in pericondri but going towards the centre of cartilage)
- become entrapped in lacunae
- mature into chondrocytes
- ->chondrocytes
- mature cells
- maintain matrix
33
What is the EMC in cartilage composed of?
ground substances and fibres (collagen and elastic):
- proteoglycans: regulate movement of molecules through matrix
- glycosaminoglycans: involved in shock absorption
- glycoproteins: binds fibres, cells and ground substance together
34
What are the different types of cartilage growth?
- -> appositional growth: (most growth)
- occurs in pericondri
- chondrogenic cells differentiate into chondroblasts
- chondroblasts mitotically divide and lay down matrix
- -> interstitial growth:
- mitotic division of chondrocytes
- increase size of matrix from within
35
What is perichondrium?
- outer layer: dense irregular connective tissue
- inner layer: chondrogenic calls and chondroblasts
- rich in blood vessels and lymphatics + afferent fibres for pain transmission
36
What are the different types of cartilage?
| Where can they be found in the body?
hyaline cartilage
elastic cartilage
fibrocartilage
37
What is the characteristic of hyaline cartilage?
| Where can it be found in the body?
- only has collagen fibres
- don't see fibres: glossy, smooth look
-ribs, larynx, trachea
38
What is the characteristic of elastic cartilage?
| Where can it be found in the body?
- elastic and collagen fibres
- looks less glossy then hyaline cartilage (can see some fibres)
-ear, eustachian tube, epiglottis)
39
What is the characteristic of fibrocartilage?
| Where can it be found in the body?
- layers of dense irregular fibres
- doesn't have perichondrium
- herring bone appearance
- chondrocytes lacunae tend to be fewer and in a row: very resilient to stress
annulus fibrosus, pubis symphasis, TMJ
40
What are the different parts of matrix around a lacunae called?
territorial matrix
| interterritorial matrix
41
What are the properties of bone?
strong and flexible
42
What does bone consist of?
--> organic component
-osteoid: glycoprotein ground substance with type 1 collagen fibres
(strong, flexible but easily compressed)
--> inorganic component
-mineral salts mainly calcium hydroxyapatite
(hard, relatively inflexible and quite brittle)
43
What are the different bone cells? What proportion of bone mass are they?
- osteoblasts: produce new bone, secrete osteoid and responsible for mineral deposition
- osteocytes: mature bone cells, located in lacunae within bone. maintain the matrix
- osteoclasts: remove mineral from matrix, responsible for bone remodelling
- osteogenic stem cells: found in periosteum and endosteum. develop into osteoblasts
44
How is compact bone structure to resist stress?
-osteons/Haversian system aligned in the same direction: unidirectional strength increase (both not resistant to stress)
-periosteum goes around circumferential lamellae
(concentric, interstitial and circumferential lamellae)
45
Where do blood vessels enter compact bone?
Volkmann canals
46
How is cancellous/spongy bone structured to resist stress?
- trabecculae of cancellous bone arranged haphazardly to form network of interconnecting struts: maximum amount of strength for minimum mass
- spaces between trabeculae contain bone marrow
- osteocytes lie in lacunae surface of the trabecullae
- -> trabecullae are orientated along lines of stress
47
What are fibroblasts compared to chondrocytes/osteocytes?
fibroblasts: non specialised connective tissue
osteocytes/chondrocytes:specialised connective tissue cells
48
What is a muscle fibre?
cell of muscle tissue
49
What is a sarcoplasm?
cytoplasm of muscle cells
50
What is a sarcolemma?
plasma membrane of muscle fibre
51
muscle unit?
muscle fibre innervated by a single motor neurone
52
motor unit?
unit of motor activity formed by one motor nerve cell and its many innervated muscle fibres
53
motor neurone pool?
collection of neurones innervating a single muscle
54
What are the different muscle types?
skeletal
cardiac
smooth
55
```
Skeletal muscle:
location
morphology
control
type of work
activity
cell shape
nuclei
```
connected to bone
striated
voluntary (somatic)
high power
usually relaxed (resting levels of muscle tone)
length of muscle (long and cylindrical in shape)
multiple nuclei, located in peripheries
56
```
cardiac muscle:
location
morphology
control
type of work
activity
cell shape
nuclei
```
```
heart
striated
involuntary (autonomic)
high power
pump (cyclic)
branch fibres, connected by interconnected disc, short
1-5 centrally located nuclei
```
57
```
smooth muscle:
location
morphology
control
type of work
activity
cell shape
nuclei
```
hollow organs
smooth
involuntary (autonomic)
low power (slow contraction: basal muscle tone)
usually contracted (varies)
short, fusiform (wider in middle, spindle form)
central (1/cell)
58
What are
endomysium
perimysium
epimysium?
connective tissue around:
endomysium: single muscle fibre
perimysium: fascicle (bundle of muscle fibres) (often have blood feels running through it)
epimysium: muscle
59
Wha are the different types of fast twitch fibres? What respiration is used?
- type IIa: intermediate fast twitch, use both aerobic and anaerobic respiration
- type IIb: use only anaerobic respiration
60
What is succinate dehydrogenase? Where do you find it? Which type of muscle fibres?
enzyme in Krebs cycle (electron transport chain)
mitochondrial membrane
--> found in slow twitch muscles
61
What are muscle spindles?
| What do they consist of?
-sensory receptors that detect muscle stretch (length)
- spindle cells: nuclear bag fibres and nuclear chain fibres surrounded by an internal capsule
- internal capsule: within fluid filled space surrounded by external capsule
- sensory nerve endings wrapped around spindle cells detect stretch
62
Why is there a reflex response?
muscle shortening to not overstretch
63
type 1 fibres (oxidative slow, red):
- myosin
- Ca pump transport rate
- diameter
- oxidative capacity
- glycolytic capacity
- fatigue
- slow
- moderate
- moderate
- high
- moderate
- resistant (++ mitochondria and myoglobin)
64
type 2B (glycolytic fast, white)
- myosin
- Ca pump transport rate
- diameter
- oxidative capacity
- glycolytic capacity
- fatigue
- fastest
- high
- large
- low
- high
- non resistant (no mitochondria)
65
type 2A (glycolytic fast, red)
- myosin
- Ca pump transport rate
- diameter
- oxidative capacity
- glycolytic capacity
- fatigue
- fast
- high
- small
- very high
- high
- resistant (few mitochondria)
