Histology Flashcards
1
Q
What are inclusions?
What are some examples?
A
They are not involved in metabolic activity/reactions.
Includes lipids, carbohydrates, pigments, secondary metabolites, granules, nutrient stores, secretory products
2
Q
What are organelles?
A
They help in metabolic activity within a cell.
3
Q
What are some characteristics of the plasmalemma/membrane?
A
- Trilaminer, selective barrier
- Phospholipids, cholesterol, proteins
- Involved in exocytosis & endocytosis
4
Q
What is the cytosol composed of?
A
It is a solution of proteins, electrolytes & carbohydrates
5
Q
What is the nuclear envelope?
A
Nuclear envelope = two layers separated by the perinuclear cistern
6
Q
What are nuclear pores?
A
Nuclear pore = Breaks in the envelope, allow transport
7
Q
What does the nucleus contain?
Where is mRNA synthesised?
Where is tRNA synthesised?
Where is rRNA synthesised?
A
The nucleus contains chromosomes & is the site of mRNA and tRNA synthesis.
On the other hand, rRNA is transcribed in the nucleolus.
8
Q
What is chromatin made up of?
A
DNA bound to proteins, make up chromosomes
9
Q
Difference between Euchromatin vs Heterochromatin
A
Euchromatin = DNA is dispersed & uncoiled, undergoing transcription.
Heterochromatin = DNA is highly condensed & coiled, not undergoing transcription.
10
Q
Small vs large subunit of a ribosome
A
Small subunit = Binds to RNA
Large subunit = Catalyses formation of peptide bonds
11
Q
What does the abundance of ER in a cell depend on?
A
The cell type & activity
12
Q
What are the 2 types of ER? And what is the function of each?
A
RER = Protein synthesis & glycoprotein formation initiation
SER = Lipid synthesis
13
Q
What is the structure of the Golgi apparatus?
What is the function of the Golgi Apparatus?
A
The Golgi apparatus is a group of flattened, membrane bound cisternae.
It receives vesicles from SER, modifies it, packages and then releases it.
14
Q
What are the 3 parts of the Golgi Apparatus?
A
Cis = Receiving end
Medial = Middle
Trans = Secreting end
15
Q
What do lysosomes contain?
A
They contain digestive enzymes - Engulf & Destroy
16
Q
What does the cytoskeleton consist of?
A
It consists of protein filaments which allow movement of organelles and also movement of the cell itself.
17
Q
What are the 3 types of protein filaments which make up the cytoskeleton?
A
- Microfilaments
- Intermediate filaments
- Microtubules
18
Q
What are microfilaments composed of?
What is the function of microfilaments?
What are their typical length?
A
Microfilaments: composed of (G&F) actin, involved in cellular movement, cytokinesis, endo & exocytosis etc., 7nm.
19
Q
What is an intermediate filament made from?
What are some functions of intermediate filaments?
What are their typical length?
A
Intermediate filaments: 6 proteins (of keratin) (that vary between cell types) that bind intracellular elements together and to the plasmalemma, >10nm.
20
Q
What are microtubules composed of?
Where do they originate?
What moves along them?
Give some examples of microtubules
A
Microtubules: composed of alpha and beta tubulin, originate from centrosome, polar, dynein and kinesin attach and move along them, 25nm. Examples include spindle, cilia and flagella.
21
Q
Structure of mitochondrial membrane
A
It is a two layered membrane, inner membrane folds forming cristae.
22
Q
A) What process occurs in the central matrix of the mitochondria?
B) What process occurs at the mitochondrial membrane?
C) What molecules are synthesised in the mitochondria?
A
A) TCA Cycle
B) Oxidative Phosphorylation
C) ATP, Lipid & Protein Synthesis take place
23
Q
What are the 4 types of intracellular junctions?
A
- Occluding Junctions
- Zonula adherens
- Desmosomes
- Communication gap junctions
24
Q
- What are occluding junctions also known as?
- What is the function of occluding junctions?
- What are occluding junctions composed of?
A
- Zonula occluden/ Tight junctions
- Prevent diffusion
- Occludin-Claudin complex + Actin
25
1. What are Zonula adherens a type of?
2. What is the function of Zonula adherens?
3. What are Zonula adherens composed of?
1. They are a type of anchoring junction
2. Provide Mechanical strength
3. Actin-link-Cadherin-link-Actin
26
1. What are desmosomes a type of?
2. What is the function of desmosomes?
3. What are desmosomes composed of?
1. Type of Anchoring junction
2. Provide mechanical strength. Common in skin.
3. Filaments-link-desmosomes-link-filaments
27
1. What are communication gap junctions also known as?
2. What is the function of communication gap junctions?
3. What are communication gap junctions composed of?
1. Gap Junctions
2. Allow selective diffusion between cells. In epithelial and some smooth & cardiac muscle cells => excitation spread.
3. Connexon proteins
28
What is a junctional complex?
Junctional complex = Close association of several junction types, found in certain epithelial tissues.
29
What does endocytosis involve?
What does exocytosis involve?
Endocytosis = Enter Cell = Endosome
Exocytosis = Leave Cell = Exosome
30
What is involved in phagocytosis?
Phagocytosis:
- Involves endocytosis
- Digestion -> phagosome
- + lysosome -> phagolysosome
31
Where are ribosomes formed?
In the nucleolus
32
What are hemidesmosomes?
Hemidesmosomes link sub membrane intermediate filaments of cells to extracellular matrix through transmembrane proteins.
33
What are the 4 types of tissue?
- Epithelial
- Connective
- Muscle
- Nervous
34
Where is epithelial tissue located?
The epithelium covers surfaces of the body, lines hollow organs and forms glands.
35
What is the epithelium backed by?
Backed by a basal lamina (basement membrane) - thin layer of specialised extracellualer material between the basal surface of epithelial cells and the underlying tissue.
36
Epithelial cells are usually polarised. What are the two different sides? And where is each side located?
Cells usually polarised - apical and basal sides differ:
- Apical: Faces the lumen of the tube or the external environment
- Basal: Attaches to the basement membrane
37
What are the 6 main functions of epithelial cells?
- Mechanical barrier - E.g. Skin
- Chemical barrier - E.g. Stomach
- Absorption - E.g. Intestine
- Secretion - E.g. Salivary glands
- Containment - E.g. Bladder
- Locomotion (by cilia) - E.g. Oviduct
38
What are the 3 different shapes of epithelial cells?
Cell Shape:
- Squamous: flattened, smaller & squashed nucleus
- Cuboidal: cube, centred & circular nucleus
- Columnar: tall and thin, nucleus near basal end
39
What are the different numbers of layers that can exist in the epithelium?
- Simple: One layer
- Stratified: 2+ layers
- Pseudostratified: Columnar, nucleus at different places in each cell
40
What are the 3 different cell surface specialisations found in epithelial tissue?
- Prominent microvilli
- Cilia
- Keratinised
41
What are microvilli?
Microvilli - Microscopic projections, Brush border, Increase surface area
42
What are cilia?
Cilia - Hair like structures, cytosol & cytoskeleton, move water & contents across cell surface
43
What does the term ‘keratinised’ refer to?
Keratinised - Protein layer on tissue, mechanical support from cells
44
What are goblet cells?
Goblet cells - Single celled mucous glands
45
What are some differences between endocrine vs exocrine cells, with regard to:
- Presence of ducts
- Area of secretion in the cell
- Where molecules are secreted into
Endocrine:
- Aka ductless glands
- Secreted towards basal end of cell
- Secretions distributed through Cardiovascular (BVs) system
Exocrine:
- Aka duct glands
- Secreted towards apical end of cell
- Into lumen, into duct or body surface
46
What is an example of a neuroepithelium?
Neuroepithelium e.g taste buds - for sensation
47
What is the purpose of a myoepithelium?
Myoepithelium - for contractility
48
What are the components which make up the connective tissue in a human body?
Composition:
- Extracellular matrix - Fibres, ground susbtances & tissue fluid
- Cells - Fibroblasts, adipose cells, osteocytes & chondrocytes
49
What do fibres include?
Fibres - Collagen, reticular & elastic fibres
50
What are ground substances made up of?
Ground substance - Made of polysaccharides/ glycoproteins
51
What are:
1. Fibroblasts
2. Adipose
3. Osteocytes
4. Chondrocytes
1. Fibroblasts - Produce extracellular matrix/fluid
2. Adipose - Fat cells
3. Osteocytes - Bone cells
4. Chondrocytes - Cartilage cells
52
What are the 3 types of soft connective tissue?
3 types: Loose, Dense Irregular & Dense Regular
53
What does loose connective tissue include?
Loose - Large, empty space/ground substance. Loosely packed fibres. Appear smooth
54
What does dense connective tissue include?
Dense - Densely packed bundles of collagen fibres. For elasticity & protection:
- Dense Irregular - Fibres run in many directions
- Dense Regular - Fibres aligned
55
What does hard connective tissue include?
What are some characteristics of this type of tissue?
Bone & Cartilage
Strong, flexible, compressible, semi-rigid
56
What are the 3 types of cartilage?
Hyaline vs elastic vs fibrocartilage
57
What are 2 components of cartilage?
Ground substances & chondrocytes
58
How does cartilage receive nutrients?
It is avascular, receives nutrients by diffusion
59
What is Hyaline composed of?
What is Elastic connective tissue composed of?
What is Fibrocartilage composed of?
Hyaline - Highly hydrated ground substances,
Elastic - Also contains elastic fibres,
Fibrocartilage - Also contains collagen fibres
60
What is the dense cortical bone?
What is the cancellous/trabecular bone?
Dense cortical bone - Outer shell of shaft (diaphysis)
Cancellous/trabecular bone - Ends of bone (epiphyses), fine mesh work, like aero bar
61
How is force produced in muscle cells?
Force - movement of actin fibres over myosin fibres with aid of accessory proteins
62
What are the 3 types of muscle?
3 types: Smooth, Skeletal & Cardiac
63
What is smooth muscle aka?
Is smooth muscle striated?
What is a characteristic of smooth muscle fibres?
Smooth muscle:
- aka involuntary or visceral muscle
- No visible striations
- Elongated fibres
64
What is skeletal muscle aka?
What is a characteristic of skeletal muscle fibres?
Do skeletal muscle fibres contain many nuclei?
Skeletal muscle:
- aka voluntary or striated
- Elongated fibres at cell periphery (sarcolemma)
- Many nuclei
65
What is cardiac muscle a major part of?
What are some characteristics of cardiac muscle fibres?
How many nuclei do cardiac muscles contain?
Why do cardiac muscle cells contain many intracellular junctions?
Cardiac muscle:
- Major part of heart chambers & vessel origins
- Striations, less prominent & involuntary
- Single nuclei at centre of fibre
- Intercalated discs, many intracellular junctions for stability
66
What are the 2 components of nervous tissue?
Neurons and glia cells (1:10)
67
What is nervous tissue surrounded by?
What is this known as in the CNS vs in the PNS?
Surrounded by connective tissue ‘coat’
Aka meninges in CNS and epineurium in PNS
68
What are the 3 neuron types?
3 neuron types:
- Multipolar - many dendrites, one axon
- Bipolar - one dendrite, one axon
- Pseudounipolar - short processes give rise to axon in both directions
69
What are the 3 main types of glia cells?
Glia cells:
- Astrocytes - Support, ion transport, induce BBB
- Oligodendrocytes e.g Schwann (PNS) or Glial (CNS) cells - Produce myelin
- Microglia - Immune surveillance
70
What type of epithelium is more likely to break, and form ulcers?
Single layered epithelium
71
What are the 4 types of connective tissue?
Soft, hard, blood & lymph
72
What is the membrane of cartilage known as?
Perichondrium
73
What is the cell membrane in skeletal muscle known as?
Cypolema
74
What is the stain H&E composed of?
H&E:
Haematoxylin -purple, basic dye
And eosin - pink, acidic dye
75
What are the 3 salivary glands?
What kind of ducts are they connected to?
Parotid, submandibular, sublingual glands
Striated ducts
76
What does each salivary gland contain a varying mix of?
Each gland contains a varying mix of serous & mucous secreting cells
- Most serous = Parotid gland
- Most mucous = sublingual
77
What is the structure and function of the striated ducts connected to the salivary glands?
Striated ducts:
- Basal cell infolding of plasma membrane & mitochondria (powers ion pump)
- Salt pumped out of secretly fluid
- Saliva more hypotonic than blood
78
What are the main structures of the GI Tract?
Mouth -> pharynx -> larynx -> oesophagus -> Stomach -> pylorus -> small intestine (duodenum, jejenum & ileum) -> Large intestine (cecum, ascending colon, transverse colon, descending colon & sigmoid colon) -> rectum -> anal canal
+ Liver, gall bladder, pancreas & appendix (Accessory glands)
79
What are the 4 major layers for the oesophagus to anal canal?
1. Mucosa
2. Submucosa
3. Muscularis externa
4. Serosa or adventitia
80
What are the 3 components of the mucosa?
Mucosa:
- Endothelium: sits on basal lamina
- Lamina propria: loose connective tissue
- Muscularis mucosae: thin layer of smooth muscle
81
What is the submucosa made up of?
Loose connective tissue
82
What is the muscularis externa made up of?
2 thick layers of thick muscle (inner circular layer and outer longitudinal layer)
83
What is the serosa and adventitia made from?
What is the difference between the serosa vs adventitia?
Serosa or adventitia = outer layer of connective tissue; either
- Suspends digestive tract (serosa) or
- Attaches to other organs (adventitia)
84
What are the 4 main types of mucosa?
- Protective mucosa
- Absorptive mucosa
- Secretory mucosa
- Protective & absorptive mucosa
85
What is a protective mucosa composed of?
Where can a protective mucosa be found?
Protective mucosa:
- Non keratinized stratified squamous epithelium
- Found in: oral cavity, pharynx, oesophagus, anal canal
86
What is a absorptive mucosa composed of?
Where can a absorptive mucosa be found?
Absorptive mucosa:
- Simple columnar epithelium with villi and tubular glands
- Small intestine
87
What is a secretory mucosa composed of?
Where can a secretory mucosa be found?
Secretory mucosa:
- Simple columnar epithelium with extensive tubular glands
- Stomach
88
What is a protective & absorptive mucosa composed of?
Where can a protective & absorptive mucosa be found?
Protective & absorptive mucosa:
- Simple columnar epithelium with tubular glands
- Large intestine
89
What is the enteric NS?
- Nervous system of the GI tract
- Ganglia between two muscle layers in muscularis externa
90
What are hepatic lobules?
What is the arrangement of a hepatic lobule?
What are some components of a hepatic lobule?
Hepatic lobules are small division of liver.
They have a hexagonal arrangement.
They contain:
- Portal triad @ each corner
- (hepatic portal vein, hepatic artery, bile duct)
- Central vein
- Receives blood from portal tract via hepatic sinusoids (which pass through sheets of hepatocytes/ hepatic lamina)
91
Does the pancreas contain exocrine or endocrine glands? Or both?
The pancreas contains exocrine & endocrine glands
92
What do the exocrine vs endocrine regions of the pancreas secrete?
Exocrine: pancreatic digestive enzymes
Endocrine: islets of Langerhans => insulin & glucagon
93
What are the different layers of the trachea?
Trachea layers:
- Lumen
- Respiratory/ mucous membrane
- Epithelium (Epithelial cells & goblet cells & glands)
- Lamina propria (connective tissue)
- Hyaline cartilage ring
94
What do goblet cells & glands in the trachea produce?
They produce viscous fluid which trap particles
95
What are bronchi?
Bronchi: large diameter airways with hyaline cartilage in their wall
96
What are bronchioles?
Bronchioles: small diameter airways, no cartilage, mainly smooth muscle
97
What are alveoli?
Alveoli: site of gas exchange, lined by simple squamous epithelium
98
What are pneumocytes?
Pneumocytes: two types, line internal surface of alveoli
99
In the large intestine, the outer longitudinal smooth muscle is not continuous. It is found in __________
It is found in 3 muscular strips called teniae coli.
100
What is the G1 phase a response to?
Is this phase reversible?
G1 is a response to growth factors, Irreversible, Majority of synthesis takes place.
101
What Cyclin and CDK is involved in the G1 Phase?
What is the impact of this Cyclin and CDK?
Cyclin E & CDKs 2:
- Phosphorylates & inactivates Rb
- EF2 is no longer inhibited
- Cyclin E & A transcribed
102
How long does the G1 Phase take?
It takes anything from less than 2 to more than 100 hours. Greater variation in length within same cell but different cycles.
103
What is the G0 Phase?
It is the non dividing phase, towards end of G1 Phase.
- Quiescent (no need to replicate)
- Senescent (damage) and differentiated
104
What does the S Phase involve?
What Cyclin and CDK is involved in the S Phase?
When does the S Phase take place, and how long does it usually take?
- DNA replication
- Cyclin A & CDKs 2
- Occurs 8 hrs after mitosis. Takes around 7-8 hrs
105
What happens in the G2 Phase?
What Cyclin & CDK is involved?
How long does this phase take?
- Nuclear membrane breaks down & chromosomes start to condense & cell is organised
- Cyclin E & CDKs 1
- Takes around 2-4 hrs
106
What are the stages involved in mitosis?
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
107
What does the prophase of mitosis involve?
- Spindle microtubules extend from the pair of centrioles
- Chromosomes condense
108
What does the Prometaphase of mitosis involve?
- Nuclear membrane and nucleolus disappear
- Around 1.5 hrs
109
What does the metaphase of mitosis involve?
- Chromosomes align
- Kinetochore presents in centromere
- Around 20 mins
110
What does the anaphase of mitosis involve?
Centromere divides longitudinally, sister chromatids separate to opposite polls by microtubules contraction.
111
What does the telophase of mitosis involve?
Nuclear membrane reforms, chromosomes decondense
112
What does cytokinesis involve?
- Cytoplasm divides
- Cleavage furrow (hour glass constriction) develops around equator region
- Contraction of fibrillar component of cytoplasm
113
What are 5 main causes of DNA damage?
- Deoxynucleotide incorporation
- Spontaneous destination of bases
- X radiation
- UV radiation
- Chemicals that interact with DNA
114
What is non disjunction?
- Abnormal function of spindles
- One or more chromosomes don’t separate properly
- One daughter cell receives an extra, and the other receives a deficient number of chromosomes
115
What is an isochromosome?
- Centromere splits transversely vs longitudinal
- Unequal daughter chromosomes
116
What is the role of Active p53?
Active p53 regulates transcription of many genes including those that code for Cyclin E/ CDKs.
117
What is the role of Rb?
Rb inhibits E2F transcription factor
118
What is the prolonged mechanism for DNA damage?
Active p53 activates p21.
This suppresses Cyclin E/ Cdk2.
Rb is dephosphorylated i.e. activated
This prevents G1 to S phase transition.
119
What is the rapid mechanism for DNA damage?
ATM + ATR protein sensors are activated
Leads to activation of Chk1 + Chk2
Cyclin E/ CDK2 become inhibited
No further progression of cell cycle
120
What parts of DNA are hydrophilic vs hydrophobic?
Deoxyribose/Phosphate backbone = hydrophilic
Base = hydrophobic
121
What can binding to minor groove prevent?
It can prevent transcription and hence prevent cell cycle
122
What is the mode of action of colchicine?
- Arrest cell division at metaphase
- Prevents microtubules formation
123
What is colchicine used for?
- Underpins rationale for many cytotoxic cancer therapy drugs
- Important in karyotyping
124
What is ubiquitin?
A protein that takes up degraded CDKs and Cyclins
125
What is the average adult blood volume?
4.5 - 6 litres
126
What % of blood is plasma?
What % of blood is leukocytes & platelets?
What % of blood is erythrocytes?
Plasma = 55% of total blood
Buffy coat leukocytes & platelets = <1% of total blood
Erythrocytes = 45% of total blood
127
What % of plasma is water?
What are other components of plasma?
Plasma components:
- Water 90%
- Proteins (albumins, immunoglobulins, clotting factors)
- Nutrients & salts
128
How can you separate the components of blood?
By centrifugation
129
What is blood serum?
Serum is plasma minus clotting factors
130
What is the shape of a RBC?
Do RBCs contain a nucleus?
What is the diameter of a RBC?
Biconcave discs
No nucleus or organelles
7um diameter
131
What makes up a 1/3 of the volume of RBCs?
Haemoglobin
132
Why do RBCs contain flexible cytoskeleton?
This allows them to fit through small spaces
133
How long do RBCs live for?
Roughly 4 months
134
How are RBCs removed?
They are removed by the spleen and liver
135
What is the Hematocrit?
Hematocrit - Proportion of blood that is RBCs
136
What are the 3 main granulocytes?
What are the 2 main agranulocytes?
What is the order of abundance of these 5 key leukocytes?
- Granulocytes (neutrophils, eosinophils, basophils)
- Agranulocytes (lymphocytes, monocytes)
Abundance = Neutrophils, lymphocytes, eosinophils, monocytes, basophils
137
Appearance of 5 key leukocytes
Eosinophils = Tomatoes with sunglasses
Lymphocytes = Round, spherical, blue nucleus & thin cytoplasm rim
Monocytes/Macrophages = Large, non lobulated, kidney bean shaped nucleus
Neutrophils = Multi lobed nucleus (granules poorly stained)
Basophils = Bilobed nucleus often obscured by granules
138
What is the mode of action of neutrophils?
They act as phagocytes (when activated)
139
How many lobes are in the nucleus of an eosinophil?
Are the granules visible in an eosinophil?
What is the function of eosinophils?
Eosinophils contain a bilobed nucleus.
And they have visible granules.
Granules with hydrolytic enzymes - Inflammation, fighting parasites
140
There are prominent granules of ______ in basophils.
How many lobes are in the nucleus of a basophil?
What is the function of basophils?
What stimulates release of granules from basophils?
Prominent granules of histamine, heparin and other inflammatory mediators.
Bilobed nucleus often obscured by granules.
Allergic reactions, IgE receptors specific to particular allergen, stimulate release of granules.
141
What do monocytes become when they migrate into tissues?
What system do they help form?
What are the granules like in a monocyte?
- Become macrophages (or dendritic cells) when migrate into tissues (especially loose connective tissue).
- Form mononuclear phagocyte system
- Many small lysosomal granules in cytoplasm
142
Do lymphocytes contain any visible granules?
What are the two categories of lymphocytes?
Where do lymphocytes originate?
Where do the T lymphocytes differentiate?
- No visible granules
- B & T cells
- Both originate in Bone marrow
- T differentiate in thymus
143
What are platelets?
What is the diameter of a platelet?
What is their key function?
What is the role of the cytoskeleton in platelets?
What is highly visible in platelets?
Platelets:
- Small cell fragments
- 2um diameter
- Key in Haemostasis, blood loss
- Cytoskeleton, involved in extrusion of granules and clot retraction
- Highly visible granules, coagulation factors etc
144
What is haemopoiesis?
Haemopoiesis - Production of BCs & platelets
145
What is a haematopoietic stem cell?
Haematopoietic stem cells (aka haemocytoblasts) - Can develop into any BC
146
In the foetal stage (2nd trimester), where is the main site of blood cell formation?
Foetal Stage/ 2nd Trimester
- Liver (and partially spleen) colonised by haematopoietic stem cells
- Liver is the main site of blood cell formation
147
Following birth, where are blood cells then produced?
Birth:
- Bone marrow is main site of blood cell formation
- All bones participate
148
As the skeleton matures, what happens to haemopoiesis, and what happens to the marrow?
Where is haemopoiesis retained?
Skeleton maturity:
- As bones enlarge, haemopoiesis stops, marrow becomes large adipose tissue
- Only vertebrae, ribs, skull, pelvis and proximal femurs retain haemopoiesis
149
What is the pathway of blood vessels (from & back) to the Heart?
1. Arteries (Elastic -> muscular arteries)
2. Arterioles -> terminal arterioles -> meta arterioles
3. Capillaries
4. Venules -> post capillary venules
5. Veins
150
What is the structural composition of an arteriole?
I.e How many smooth muscle layers are there?
Does it contain an adventitia?
Is the diameter small or large?
Arterioles:
- 1 or 2 smooth muscle layers in tunica media (less)
- Almost no adventitia
- Smaller diameter and lumen
151
What is the structural composition of a terminal arteriole?
I.e Is there an internal lamina present?
What is the smooth muscle like?
Terminal arterioles:
- No internal lamina
- Continuous coat of smooth muscle cells
152
In meta arterioles, what is the smooth muscle replaced with?
Smooth muscle replaced with dis continuous non contractile cells called pericytes.
153
What are the 2 layers which make up the capillaries?
Endothelial cells and a basal lamina
154
Capillaries are found almost everyone in the body, where are some exceptions?
They are not found in epithelial cells (epidermis of skin hair and nails etc), eye cornea & hyaline cartilage
155
What are the 3 types of capillaries?
What size of pores do each of these types display?
Where are each of these types found in the body?
- Continuous
- No pores
- Muscle, nerve, lung and skin
- Fenestrated
- Small pores
- Gut mucosa, endocrine glands, kidney
- Discontinuous/ sinusoidal
- Large gaps
- Liver, spleen, bone marrow
156
What are the 2 layers of post capillary venules?
Endothelium & connective tissue
157
What are the 3 layers of venules?
Endothelium, Connective tissue & intermittent smooth muscle cells in tunica media
158
What are the 3 layers of the veins?
Veins:
- Tunica intima
- Thin continuous tunica media
- Thick tunica adventitia
159
What are the 6 layers that can be found in a blood vessel?
- Lumen
- Tunica intima
- Internal elastic membrane (Basal lamina)
- Tunica media
- External elastic membrane
- Tunica adventitia
160
What is the tunica intima?
Tunica intima:
- Inner layer
- Single layer of squamous epithelial cells (endothelium), thin layer of connective tissue & basil lamina
161
What is the tunica media?
Tunica media:
- Middle layer
- Mainly smooth muscle & possible elastic fibres (depending on type of blood vessel)
162
What is the tunica adventitia?
Tunica adventitia:
- Outer layer
- Supporting connective tissue
163
Does the lymph vasculature contain a central pump?
No, there is no central pump
164
What stimulates flow in lymph vessels?
Smooth muscle in walls, hydrostatic pressure in tissue and compression of vessel by voluntary muscle and valves = flow
165
Large elastic arteries have their own vascular supply, what is this known as?
Large elastic arteries e.g aorta - Have their own vascular supply known as Vasa Vasorum
166
What are vein valves?
Vein valves = Inward extension of tunica intima
167
What are thoroughfare channels?
Thoroughfare channels - Connect directly from arteriole to vein, give rise to capillaries via precapillary sphincters
