IMMS Histology Flashcards
(159 cards)
1
Q
Epithelial cells (examples)
A
- Gut and blood vessel lining
- Covering skin
2
Q
3 functions of Epithelial cells
A
1 - Barrier
2 - Absorption
3 - Secretion
3
Q
Special feature of Epithelial cells
A
Tightly bound together by cell junctions
4
Q
Support cells (examples)
A
- Fibrous support tissue
- Cartilage
- Bone
5
Q
Function of Support cells
A
Organise and maintain body structure
6
Q
Special features of Support cells
A
Produce and interact with extracellular matrix material
7
Q
Contractile cells (example)
A
Muscle
8
Q
Function of Contractile cells
A
Movement
9
Q
Special features of Contractile cells
A
Filamentous proteins cause contractions
10
Q
Nerve cells (example)
A
Brain
11
Q
Function of Nerve cells
A
Direct cell communication
12
Q
Special features of Nerve cells
A
Release chemical messengers on to surface of other cells
13
Q
Germ cells (example)
A
Spermatozoa
14
Q
Function of Germ cells
A
Reproduction
15
Q
Special features of Germs cells
A
Half normal chromosome compliment
16
Q
Blood cells (examples)
A
Circulating red and white blood cells
17
Q
2 Functions of Blood cells
A
1 - Oxygen transport
2 - Defence
18
Q
Special features of Blood cells
A
- Proteins bind oxygen
- Proteins destroy bacteria
19
Q
Immune cells (examples)
A
Lymphoid tissues and White cells
20
Q
Function of Immune cells
A
Defence
21
Q
Special features of Immune cells
A
Recognise and destroy foreign material
22
Q
Hormone secreting cells (examples)
A
- Thyroid
- Adrenal
23
Q
Function of Hormone secreting cells
A
Indirect cell communication
24
Q
Special features of Hormone secreting cells
A
Secrete chemical messengers
25
Alcian Blue dye
What structures does it stain? (4)
What colour?
1 - GAG-rich structures
2 - Mucous goblet cells
3 - Mast cell granules
4 - Cartilage matrix
BLUE
26
Eosin dye
What structures does it stain? (2)
What colour?
1 - Colloidal proteins (plasma)
2 - Keratin
PINK / RED
27
Haematoxylin dye
What structures does it stain? (2)
What colour?
1 - Nuclei
2 - RNA
BLUE
28
Periodic Acid Schiff (PAS)
What structures does it stain?
What colour?
Hexose sugars - especially those in complex carbohydrate structures including Goblet cell mucins, cartilage matrix, glycogen, basement membranes, glycocalx
MAGENTA
29
Giemsa stain
What structures does it stain?
What colour?
Chromatin - PURPLE
Erythrocytes - PINK
Lymphocyte & Monocyte cytoplasm - PALE BLUE
30
Van Gieson's trichrome dye
What structures does it stain?
What colour?
Collagen - PINK / RED
Cell cytoplasm - YELLOW / GREEN
Nuclei - BLACK
31
Common structure of cell membranes
A lipid bilayer containing specialised proteins and surface carbohydrates
32
The main membrane-bound compartments of the cell (7) and their functions
1 - Nucleus, contains DNA
2 - Mitochondria, provide energy
3 - Endoplasmic Reticulum (ER), biosynthesis of protein and some lipids
4 - Golgi, processing biosynthetic products for incorporation into the cell or secretion
5 - Vesicles, transport material around the cell
6 - Lysosomes, digest macromolecules
7 - Peroxisomes, contain enzymes involved in fatty acid metabolism
33
Cell structure
- Outer membrane to separate it from the environment and other cells
- Contain proteins, electrolytes and carbohydrates (cytosol)
- Cytoskeleton, composed of filamentous proteins (intermediate filaments, actin and microtubules)
34
3 major types of membrane lipid
1 - Phosphoglycerides (phospholipids)
2 - Cholesterol
3 - Glycolipids
35
Functions of membrane proteins (5)
1 - Attach cytoskeletal filaments to the cell membrane
2 - Attach cells to the extracellular matrix
3 - Transport molecules in / out of the cell
4 - Act as receptors for chemical signalling
5 - Possess specific enzymatic activity
36
Function of Ribosomes
It is the site of protein synthesis
37
What is Cytosol comprised of?
- The 'machinery' involved in protein synthesis
- Filamentous proteins
- Products of metabolism e.g. glycogen and free lipids
- Ribosomes, found freely in the cytosol and also as part of R.ER
38
What is the Nucleus comprised of?
- cellular DNA
- The nucleolus
39
Which filamentous proteins form a scaffold within the inner nuclear membrane to maintain the Nucleus' spherical shape?
Lamins
40
Which proteins does DNA wind around to form nucleosomes?
Histones
41
The two forms of chromatin
Euchromatin - lightly stains and is actively transcribed cellular DNA
Heterochromatin - dense staining area due to being highly condensed, is transcriptionally inactive
42
The site of formation of ribosomal RNA in the nucleus
The Nucleolus
43
What is apoptosis?
A form of programmed cell death where the cell shrinks, becomes fragmented, and is ingested by adjacent cells
44
Classifications of Epithelial cells - shape (3)
1 - Squamous (flat, plate-like
2 - Cuboidal
3 - Columnar
45
Classifications of Epithelial cells - layers (3)
1 - Simple (single layer of cells)
2 - Stratified (many layers of cells)
3 - Pseudostratified (several layers of NUCLEI BUT all cells in contact with the extracellular matrix)
46
Epithelial cell junctions (4)
1 - Occluding / Tight
2 - Anchoring
3 - Communicating / Gap
4 - Desmosomes
47
Functions of Tight / Occluding junctions
1 - Prevention of diffusion of molecules between adjacent cells (barrier)
2 - Prevention of lateral migration of specialised cell membrane proteins
48
Functions of Anchoring junctions
Provide stability to groups of epithelial cells so they can function as a cohesive unit
49
Functions of Desmosomes
Connect two cells together using link proteins. Mainly found in stratified squamous epithelium covering the skin
50
Functions of Communication / Gap junctions
Allow selective diffusion of molecules between adjacent cells and facilitate cell-to-cell communication.
Important in Cardiac and Smooth muscle (involuntary) where they pass signals involved in contraction from one cell to another
51
Mechanisms to increase surface area of epithelial cells (3)
1 - Microvilli
2 - Basolateral folds
3 - Membrane plaques
52
What are Cilia?
Hair-like projections, o.2 um in diameter, which move fluid over the cell surface or confer cell motility
53
The functions of cell surface proteins (3)
1) Enzymes
2) Adhesion molecules
3) Cell recognition
54
Features of mucin-secreting epithelial cells (2)
1) Well developed basal rough ER
2) Well developed supra nuclear Golgi
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Features of steroid-secreting epithelial cells (3)
1)Well developed smooth ER
2) Free lipid in vacuoles in the cell cytoplasm
3) Prominent mitochondria with tubular cristae
56
Features of Ion-pumping epithelial cells (3)
1) Folded cell membrane to increase the active surface area
2) Large numbers of mitochondria closely apposed to the membrane folds to supply ATP
3) Tight junctions to prevent back diffusion
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What is Merocrine secretion?
Secretion of cell products by exocytosis from the cell apex into a lumen (exocrine)
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What is Apocrine secretion?
The pinching off of the cell cytoplasm containing cell products (exocrine)
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What is Holocrine secretion?
Shedding of the whole cell containing the cell product (exocrine)
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What does the term Exocrine mean?
Secretions from the apex of the cell on to a surface or into a lumen
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What does the term Endocrine mean?
Secretions from the side or base of the cell which enter the blood stream directly
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What is Capillary secretion?
Secretion of cell products by endocytosis. Where cell products from the basal layer enter the blood stream
63
Explain keratinisation
Occurs in stratified squamous epithelial cells.
The cytoskeleton becomes tightly condensed with other specialised proteins to form a mass.
This triggers cell death and the formation of a tough impervious and protective layer - keratin.
This remains attached to underlying cells by anchoring junctions.
64
Where do you find simple squamous epithelium?
- Air sacs of lungs
- Lining of the heart
- Blood vessels
- Lymphatic vessels
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Where do you find simple cuboidal epithelium?
- Ducts and secretory portions of small glands
- Kidney tubules
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Where do you find simple CILIATED columnar epithelium?
- Bronchi
- Uterine tubes
- Uterus
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Where do you find simple NON-CILIATED columnar epithelium?
- Digestive tract
- Bladder
68
Where do you find pseudostratified CILIATED columnar epithelium?
- Trachea
- Upper respiratory tract
69
Where do you find stratified squamous epithelium?
- Oesophagus
- Mouth
- Vagina
- Anal canal
70
Where do you find stratified cuboidal epithelium?
- Sweat glands
- Salivary glands
- Mammory glands
71
Where do you find stratified columnar epithelium?
- Male urethra
- Ducts of some glands
72
Where do you find transitional epithelium?
- Bladder
- Uretha
- The ureters
73
Name the FOUR fibrillar proteins
1) Collagen
2) Fibrillin
3) Elastin
4) Fibronectin
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Collagen Type I distribution
Skin
Dermis
Tendon
Bone
Ligaments
Fibrous cartilage
Loose fibrous tissue
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Collagen Type II distribution
Hyaline and elastic cartilage
Vertebral discs
Vitreous of eye
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Collagen Type III distribution
Blood vessels
Liver
Kidney
Spleen
Uterus
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Collagen Type IV distribution
Basement membranes
External laminae
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Collagen Type V distribution
Placenta
Smooth muscle
Skeletal muscle
79
Name the FOUR layers of the epidermis
Basal layer
Prickle cell layer
Granular layer
Keratin layer
80
In which layer of the epidermis are keratinocytes produced?
Basal
81
What forms the price cell layer?
Keratinocytes
81
What forms the price cell layer?
Keratinocytes
82
In which layer is the surface keratin formed?
Granular
83
Main role of Langerhans' cells?
Antigen recognition
84
The FIVE main classes of support cell
1) Fibroblasts
2) Chondrocytes
3) Osteoblasts
4) Myofibroblasts
5) Adipocytes
85
Define Fibroblasts
Secrete the extracellular matrix components in most tissues, usually collagen and elastin
86
Define Chrondrocytes
Secrete the extracellular matrix components of cartilage
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Define Osteoblasts
Secrete the extracellular matrix components of bone
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Define Myofibroblasts
Secrete extracellular matrix components and also have a contractile function
89
Define Adipocytes
Lipid-storing support cells. Storing energy and also act as cushioning / padding
90
Name the TWO major materials that make up the extracellular matrix in support cells
1) GAG - glycosaminoglycans
2) Fibrillar proteins
91
Explain GAG
Glycosaminoglycans are large, unbranched polysaccharide chains composed of repeating disaccharide units (70-200 residues).
Strongly hydrophilic because they cannot fold into compact structures, so have a large, open coil conformation.
92
Where is the GAG, Hyaluronic acid found?
Cartilage
Synovial fluid
Skin
Support tissue
93
Where is the GAG, Chondroitin sulphate found?
Cartilage
Bone
Skin
Support tissue
94
Where is the GAG, Dermatan sulphate found?
Skin
Blood vessels
Heart
95
Where is the GAG, Heparan sulphate found?
Basement membrane
Lung arteries
96
Where is the GAG, Heparin found?
Lung
Liver
Skin
Mast cell granules
97
Where is the GAG, Keratan sulfate found?
Cartilage
Cornea
Vertebral disc
98
Define Elastin
A hydrophobic protein which assembles into filaments and sheets by cross-linking.
It is the main component of elastic fibres and is produced by fibroblasts.
99
Explain what Microfibrils are
They contain fibrillin, a glycoprotein, and are 8 - 12 nm in diameter.
They are prominent in elastic-containing extracellular matrix, particularly in lung, skin and blood vessel walls.
100
The THREE forms of the multifunctional glycoprotein, Fibronectin
1) A circulating plasma protein
2) A transient protein that attaches to the surface of many cells
3) Insoluble fibrils forming part of the extracellular matrix
101
The FIVE major components of basement membranes
1) Type IV collagen
2) Laminin
3) Heparan sulphate
4) Entactin
5) Fibronectin
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Laminin
A sulphated glycoprotein.
A major extracellular link molecule between cells and extracellular matrix.
103
Entactin
A sulphated glycoprotein.
Functions as a link protein binding laminin to Type IV collagen.
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Tenascin
An extracellular glycoprotein.
Particularly expressed in embryonic tissue.
105
The THREE main functions of Basement Membrane
1) Adhesion interface
2) Permeability barrier
3) Controls cell organisation and differentiation
106
The FOUR junctions between cells and the extracellular matrix
1) Hemidesmosomes
2) Focal contacts
3) Laminin receptors
4) Non-integrin glycoproteins
107
The functions of Fibrocollagenous tissues (5)
1) Support - nerves, blood vessels, and lymphatics
2) Separation of functional layers in organs and tissues
3) Support - transient and resident immune cells
4) Formation of fibrous capsule - liver, spleen, kidneys
5) Formation of fibroadipose tissue - encloses and blends with adipocytes
108
The THREE types of cartilage
1) Hyaline - contains Type II collagen only
2) Fibrocartilage - contains Type I and II collagen
3) Elastic - contains Elastic fibres and Type II collagen
109
Name the FOUR main groups of contractile cell
1) Muscle cells
2) Myofibroblasts
3) Pericytes
4) Myoepithelial cells
110
Name the main constituents of thin and thick filaments found in skeletal muscle
Thin - Actin (anchored to the Z line)
Thick - Myosin (anchored to the M line)
111
What powers the contraction of skeletal muscle
The hydrolysis of ATP
112
What gives striated muscle this appearance?
The close alignment of actin and myosin filaments
113
Where is Smooth muscle found?
The walls of most hollow viscera (gut, urinary bladder, uterus)
Blood vessels
114
Describe Smooth muscle
- Spindle shaped
- Sized from 20 um - 500 um
- Single centrally located nucleus which is elongated in shape
- Each cell is surrounded by an external lamina
- Organised into bundles
115
Explain the TWO types of Smooth muscle
Tonic and Phasic.
Characterised by arrangement and speed of contraction.
116
What are the TWO main circulatory systems?
1) Blood
2) Lymphatic
117
What are the TWO main Blood circulatory systems?
1) Systemic
2) Pulmonary
They depend on the heart. There is a third system - portal - this uses specialised vascular channels to carry substances from one site to another. It does not depend on a central pump (heart).
118
Explain Systemic circulation
Transfers oxygenated blood from the heart to body tissue and returns de-oxygenated blood, with a high CO2 content, back to the heart.
119
Explain Pulmonary circulation
Transfers de-oxygenated blood, with a high CO2 content, from the heart to the lungs (pulmonary arterial system) and returns re-oxygenated blood from the lungs back to the heart (pulmonary venous system).
120
Name the TWO systemic blood vessels
1) Arteries
2) Veins
121
What are Arteries for?
To carry blood AWAY from the heart towards the capillary system, under high pressure
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What are Veins for?
To carry blood TOWARDS the heart, from the capillary system, at low pressure
123
Why does the LEFT VENTRICLE have a large component of elastic tissue?
The systemic arterial circulation is a high pressure system. It needs the elasticity to manage the high pressure under which it is subjected.
124
Give an example of a LARGE ELASTIC ARTERY
The Aorta, and its large branches e.g. the carotid
125
What is the term for the smaller, muscular arteries distal to the large elastic arteries?
Arterioles
126
Explain the structure of Arteries
- In the centre is the LUMEN. The channel through which blood flows
- Surrounding this a layer of Squamous Endothelial cells which rest on a basement membrane
- Surrounding this is a thin layer of loose connective tissue called the INTIMA
- In turn this is bound by a layer of elastic tissue - Internal Elastic Lamina
- Surrounding this is a thick layer of connective tissue called the MEDIA
- Surrounding its outer layer is a layer of elastic tissue - External Elastic Lamina
- The final layer comprises loose connective tissue and is called the ADVENTITIA
127
What doe the MEDIA layer comprise?
Smooth muscle
Fibroblasts
Collagen
Elastin
128
Explain the structure of Capillaries
A layer of vascular Endothelial cells resting on the inside of a Basement membrane
129
How are Elastic arteries characterised?
Multiple elastic laminae in the media
130
How are Muscular arteries characterised?
Media comprised almost entirely of smooth muscle
131
Name the TWO types of Capillary
1) Continuous
2) Fenestrated
132
Explain what is meant by Continuous Capillaries
The Endothelial cells form a complete internal lining with no defects. These are tightly attached.
133
Explain what is meant by Fenestrated Capillaries
The Endothelial cell cytoplasm is pierced by pores, which extend through its full thickness.
These pores allow for free diffusion.
These are found most commonly in the GI mucosa, Endocrine glands, and Renal glomeruli.
134
Explain the structure of Veins
The Lumen is larger and the Media thinner in comparison to arteries. And there is no External elastic lamina.
135
Where are Arteriovenous anastomoses most common?
Fingertips
Lips
Nose
Ears
Toes
136
What is Arteriovenous anastomoses?
Direct connections between small arteries and small veins
137
What is the function of the Lymphatic system?
To carry fluid that drains from intercellular space of tissues
138
What is the function of Nerve cells?
Direct communication between different groups of cells
139
Explain the regions of Neurons
- A cell body containing the nucleus and most of the organelles
- An Axon
- Dendrites
- Synapses (specialised cell junctions)
140
Why do Neurons need to be highly metabolically active?
- To maintain a massive surface area of cell membrane
- To develop electrochemical gradients
141
What type of Neurons do Motor neurone tend to be?
Multipolar
142
What type of Neurons do Sensory neurone tend to be?
Unipolar
143
What type of Neurons do Interneurons tend to be?
Bipolar
144
What is Neuron signalling controlled by?
An electrical (ionic) gradient across the cell membrane
Firing is associated with depolarisation of the cell membrane which, in a resting axon, has a negative membrane potential.
Electrical depolarisation is mediated by Ion channels in the cell membrane.
145
Describe a Synapse
A special type of cell junction that allows direct communication between cells.
In this instance a transmitter substance is secreted in a highly localised fashion by one cell and received uniquely by another.
146
THREE possible effects of transmitter release
1) Depolarisation
2) Hyperpolarisation
3) Altered cell sensitivity
147
The composition of Ganglia
- Neuron cell bodies
- Support cells (satellite cells and Schwann cells)
- Axons
- Loose fibrocollagenous support tissue
148
What is the CNS?
The Central Nervous System.
This comprises the brain and spinal cord. Within these are found nerve cells and their processes, together with specialised support cells - glia.
149
List the FOUR Glial cells
1) Astrocytes
2) Oligodendrocytes
3) Ependyma
4) Microglial
150
The functions of Astrocytes (3)
1) Embryogenesis
2) Fluid transport
3) Structural support
151
The main function of Oligodendrocytes
Myelin production
152
The role of Ependymal cells
To line the cavities in the brain and the central canal of the spinal cord, forming a sheet of cuboidal cells in contact with the cerebrospinal fluid
153
What is the specialisation of Microglia?
Immunity
154
What is the PNS?
Peripheral Nervous System
155
What is a Nerve?
A collection of axons, linked together by support tissue
156
What is a Ganglion?
A peripheral collection of nerve cell bodies together with efferent and afferent axons, and support cells.
157
Explain the term Peripheral nerve
Bundles of axons associated with support tissue. They comprise Axons, Schwann cells, Spindle-shaped fibroblast support cells, and Blood vessels.
158
Name the THREE types of support tissue found in a nerve trunk
1) Endoneurium
2) Perineurium
3) Epineurium
