Tissues Of The Body Flashcards
(232 cards)
0
Q
What different types of glands are there?
A
- Simple
- Compound
1
Q
Describe the difference between endocrine and exocrine.
A
- Exocrine: glands with ducts
- Endocrine: ‘ductless glands’ secrete directly into the bloodstream.
2
Q
What different types of secretions are there?
A
- Mucous: mucus rich in mucins
- Watery and free of mucus secretions
3
Q
What is a visceral and parietal pleura?
A
- Visceral (inner)
- Parietal (outer)
4
Q
What are the 4 layers of the intestinal lining?
A
- Mucosa
- Submucosa
- External muscular layers
- Serosa
5
Q
What layers does the mucosa consist of?
A
- Muscularis mucosae
- Lamina propria
- Epithelium
6
Q
What is the Submucosa?
A
- Layer of connective tissue bearing glands, arteries, veins and nerves
7
Q
How are luminal contents moved along the intestine?
A
- 2 layers of smooth muscle form Muscularis externa which create a peristaltic wave
8
Q
What is exocytosis also known as and what is it?
A
- Merocrine secretion
- Membrane bound component approaches cell surface
- Fuses with plasma membrane
- Contents are released into extracellular space.
- Membrane reforms.
9
Q
What is Apocrine secretion?
A
- Non membrane bound structure moves to cell surface
- Contact and pushes up apical membrane
- Apical cytoplasm surrounds droplet
- Membrane surrounding droplet pinches off
- Membrane added to regain SA
10
Q
What is holocrine secretion and where is it found?
A
- Disintegration of cell
- Release of contents
- Discharge of whole cell
- ONLY in sebaceous glands
11
Q
What is transepithelial transport?
A
- Endocytosis at one surface
- Transport vesicle shuttles across cytoplasm
- Exocytosis at opposite end.
12
Q
What is the function if the Golgi apparatus?
A
- Sorting into different compartments
- Packaging via condensation of contents
- Glycosylation (addition of sugars to proteins and lipids)
- Transport
13
Q
What happens to the products of the Golgi?
A
- Majority to secretory vesicles
- Retained in cells for use (lysosomes)
- Transported to plasma membrane (Glycocalyx)
14
Q
What is Glycocalyx?
A
- Sweet husk, proteoglycans, glycoprotein and glycolipids
- Protection of epithelial cells
- Intracellular communication
- Intracellular adhesion
- Intracellular adhesion
15
Q
What are the different types of secretion control?
A
- Nervous (sympathetic stimulation of adrenal medullary cells for adrenaline)
- Endocrine (stimulates cortex of adrenal gland to secrete hormones)
- Neuro-endocrine (nervous cells stimulate hormone secretion)
16
Q
Give 3 examples of exocrine secretion.
A
- Unicellular gland in jejunum and colon
- Parotid glands
- Submandibular glands
17
Q
Give 3 examples of endocrine secretion.
A
- Pancreas
- Thyroid
- Adrenal (suprarenal)
18
Q
Where in the body can mucous membranes be found?
A
Linings of internal tubes that have contact with the exterior environment, e.g respiratory tract
19
Q
Where is a serous membrane and where is it found?
A
- Thin, two part membranes which line closed bodily cavities to secrete a lubricating fluid, to allow friction free movement of structures they surround.
- Peritoneum (abdominal organs)
- Pleural sacs (lungs)
- Pericardial sacs (heart)
20
Q
What are serous membranes composed of?
A
- Simple squamous epithelium, secretes watery lubricating fluid
- Thin layer of connective tissue.
21
Q
What are the different types of biopsies and where on the body are they use?
A
- Smear: cervix, buccaneer cavity
- Curettage: endometrial lining of the uterus
- Needle: brain, breast, liver, kidney, muscle
- Direct incision: skin, mouth, larynx
- Endoscope: lungs,intestine,bladder
- Transvascular: heart, liver
22
Q
What are the 3 main types of stain and what do they stain?
A
- Haematoxylin - acidic components (nucleus/chromatin) blue/purple
- Eosin - basic (cytoplasmic proteins, extra cellular fibres) pink
- Periodic Acid Schiff - (glycoproteins, carbohydrates) magenta
23
Q
How does processing of a specimen lead to shrinkage artefacts?
A
- Dehydration, rehydration and dehydration again
24
Why do tissues need repair?
- Preserves cell structure
| - Prevents autolysis and putrefaction
25
What is an epithelium?
- Sheets of contiguous cells, varying in origin, that line the inner surfaces and cover outer surfaces.
26
Where is the basement membrane found and what is it's function?
- Between epithelial tissues and connective tissue
| - Strong flexible layer for cellular adhesion and a molecular filter.
27
Where are pseudostratified cells found in the body?
- Upper nasal cavity
- Ear
- Upper respiratory system
28
Where are simple squamous cells found and what's their roles?
- Blood vessels (active transport by pinocytosis)
- Mesothelium (to secrete for lubrication)
- Alveoli (gas exchange)
29
What are stratified squamous' role and where are they found?
- Prevent wear loss, UV damages, abrasion
- Skin
- Vagina
- Anus
- Oesophagus
30
Where are cuboidal cells found, what are their roles?
- Ducts of exocrine glands
- Kidney tubules
- Absorption, hormone secretion.
31
Where are columnar cells found and what are their roles?
- Small intestine & colon (absorption, secretion & lubrication)
- Stomach lining & gastric glands (secretion)
- Gall bladder (absorption)
- Uterus
- Oviduct (transport)
32
What are transitional epithelium?
- Layers of cells that have the ability to change shape from cuboidal (relaxed) to squamous (tense)
33
Where are transitional epithelium found and its role?
- Bladder, ureters.
| - Distension and protection of underlying tissues
34
How long does it take for skin cells to 'die'?
- 28 days.
35
Where are keratinised stratified squamous cells found and their roles?
- Skin surface
- Linings of surfaces exposed to the exterior.
- Protection against abrasion & physical trauma
- Prevents water loss, ingress of microbes.
36
Where are stratified columnar found?
- Conjunctiva of eye
| - Lining some large excretory ducts.
37
Where are stratified cuboidal cells found?
- Lining ducts of sweat glands.
38
Where does glycosylation of proteins occur?
- Golgi apparatus
39
What is the process of glycosylation?
- Addition of sugars to proteins and lipids.
| - Glycocalyx formation (intercellular communication, adhesion to substrates, contact inhibition)
40
What are the 4 ways of controlling secretion?
- Neural control (sympathetic stimulation of adrenal medullary cells)
- Hormone control (ACTH promotes secretion of adrenal cortex hormones (cortisol)
- Neuro-endocrine (hypothalamus controls ACTH production)
- Negative feedback (inhibition of production)
41
What is the limit of resolution?
- The minimum distance between two points that still allow them to be individually resolved.
42
Why are electron microscopes better at resolving than light microscopes?
- Shorter wavelength, better resolution
| resolution is proportional to wavelength
43
What is heterochromatin?
- Dark in colour, dense & unexpressed
44
What is euchromatin?
Light in colour, less dense and expressed.
45
What is a nucleolus?
- Contains RNA for ribosome synthesis and assembly.
46
What is the role of the Rough Endoplasmic reticulum?
- Synthesise proteins
47
What is the role of the SER?
- Biosynthesis of lipids
- Steroid production
- intracellular transport
48
What is the role of the Golgi with respect to proteins?
- Modify, sort and package proteins from the RER
- Movement from Cis to the Trans side.
- Secretion in vesicles or formed into lysosomes.
49
What is the role of peroxisomes?
- Detoxification (eg alcohols)
| - Production and utilisation of H2O2
50
What subunits make up the cytoskeleton and what is its overall role?
- Microtubules
- Microfilaments
- Intermediate filaments
- Allow for transport of cellular constituents
- Maintain the shape & structure of the cell
51
What components form connective tissue?
- Cells
- Ground substance
- Fibres: collagen, reticular, elastic
52
What is the role of ground substance?
- Resistant to impact due to jelly like composition.
53
What are the roles of the 4 different types of collagen?
1: Fibres/fibre bundles
2: Elastic cartilage
3: Reticulum (fibres around muscle and nerve cells)
4: Present in basal lamina
54
What is the definition of connective tissue?
- Forms continuum throughout the body, provides metabolic and physiological support, links epithelium, nerves and muscles.
55
Elastic fibres contain what two components?
- Elastin
| - Fibrillin (surrounds enfolded elastic fibres)
56
What is the role of fibroblasts?
- Synthesises and secretes fibres and ground substance.
| Important in wound healing and cells responsible for scar tissue
57
What are macrophages and their role?
- Phagocytic, degrade foreign organisms and cell debris
| Effectively a phagocyte but in connective tissue
58
What is the role of mast cells?
- Abundant in granules eg. anticoagulant
| - Mediate hypertension and allergic reactions.
59
What is the function of the extracellular matrix?
A hydrating gel.
60
What is the difference between dense and loose connective tissue?
- Dense: more fibres, less ground substance.
| - Loose: fewer fibres, more ground substance.
61
What's the difference between irregular and regular dense tissue?
- Irregular, fibres run in all different directions, can resist force in all directions.
- Regular, fibres all run in the same direction, very strong in the direction they run, tendons.
62
Cells from cartilage are known as?
- Chondrocytes
63
The extracellular matrix of cartilage contains a high ratio of GAGs, what does this allow?
- Diffusion between chondrocytes and blood vessels.
64
What is the role of Hyaline cartilage?
- Precursors to bone development by endochondral ossification.
- Present in articulating surfaces (connects ribs to sternum, parts of the respiratory tract)
- Calcifies with age.
65
What is fibrocartilage?
- Mix of chondrocytes and fibroblasts.
- Combination of dense regulator connective tissue and hyaline cartilage.
- No surrounding perichondrium
- Sites: intervertebral discs, articular discs of joints, meniscus of knee joint and pubic symphysis.
- Shock absorber, resists shearing forces
66
What is elastic cartilage and its role?
- Many elastic fibres in ECM giving elasticity and resilience.
- Doesn't calcify with age.
- Sites: External ear, epiglottis, Eustuchian tube.
67
When adults damage chondrocytes how is it repaired?
- Can't undergo mitosis of chondrocytes, so deposition of fibrous scar tissue fills the area.
68
What are the 4 main parts of the bone?
- Spongey bone (deeper and porous, highly vasculated)
- Compact bone (dense, hard, outer layer, Haversian and Volksmann canals)
- Periosteum (tough, vasculated, surrounds bone)
- ECM (Collegenous fibres in calcified matrix)
69
What is caniliculi?
- Cytoplasmic process, connecting osteocytes that allow the sharing of nutrients.
70
Outline the bone remodelling system.
- Osteoclasts, 'cutting cone' release of H+ and lysosomal enzymes
- Osteoblasts, form new bone.
71
What are the 3 main macroscopic appearances of the skin and what are they effected by?
- Colour: UV exposure, location, ethnicity
- Hair: Site, sex, ethnicity, age
- Laxity: Age, UV exposure.
72
What is Vitiligo?
- Autoimmune depigmentation of the skin.
- Tends to be symmetrical.
- More obvious on dark people.
73
What is Alopecia?
- Autoimmune reaction causing loss of hair.
| - Greater psychological effect on women.
74
What are the 4 strata of the skin?
- Horny (corneum)
- Granular
- Prickle
- Basal
75
What happens in each of the stratum of the skin?
- Basal: Keratinocyte mitosis
- Prickle: Lose ability to differentiate, keratins synthesised.
- Granular: Lose plasma membrane, differentiate into corneocytes, keratins and other fibrous proteins are aggregated.
- Horny: Flattened corneocytes.
76
What are Langerhans cells?
- Mediate an immune response, they're antigen presenting cells.
- Dendritic cells of bone marrow origin.
- Scattered through prickle layer.
77
What are melanocytes and their role?
- Occurs at intervals in the basal layer.
| - Produce melanin (darker people have the SAME number of melanocytes just produce more)
78
What is produced from hair follicles and what for?
- Sebum
- Lubrication
- Waterproofing
79
What are sweat glands primarily for?
- Thermoregulation.
80
Name 3 characteristics of the dermis and its components.
- Tough
- Vascular
- Fibrous
-ECM, blood vessels, nerves, lymphatics, mast cells.
81
What is the main effect of Psoriasis?
- Major protein, fluids and heat loss.
82
What's malignant melanoma?
- Cancer of melanocytes
| - Can't cure once penetrated the basal membrane.
83
What are the main functions of the skin?
- Barrier
- Sensation
- Thermoregulation
- Psychosexual communication.
84
What are the 3 types of Cartilage?
- Hyaline
- Elastic
- Fibrocartilage
85
What does GAG stand for in reference to cartilage and what is its role?
- Glycosaminoglycans
| - Allows diffusion between chondrocytes and blood vessels.
86
Give 3 characteristics of Hyaline cartilage.
- Matrix with proteoglycans
- Single/small clusters (isogenous groups)
- Precursor model for bones, so found in early foetal development (development by endochondral ossification)
87
Where is Hyaline cartilage found?
- Shoulder
- Elbow
- Wrist
- Feet
88
What are the characteristics of elastic cartilage.
- Many elastic fibres in ECM. = elasticity and resilience.
| - Doesn't calcify with age
89
Where is elastic cartilage found?
- External ear
- Epiglottis
- Eustuchian tube.
90
What are the characteristics of fibrocartilage and its role?
- fibroblasts + chondrocytes
- dense regular connective tissue + hyaline cartilage
- Synthesise and secrete both ground substance and fibres found in ground substance.
- Primarily responsible for scar tissue.
91
Where is fibrocartilage found?
- Intervertebral discs
- Articular discs of joints
- Menisci of joints
- Pubic symphysis
92
What does connective tissue compose of?
- Extracellular matrix
- Ground substance (jelly like)
- Fibres (collagen, reticular, elastic)
93
Is mesochyme totipotent, multipotent or specialised?
- Multipotent
94
What's ground substance's role?
- Impact resistance.
95
What are the roles of the 4 different types of collagen?
- 1: Fibrils aggregate into fibres and fibre bundles
- 2: Elastic cartilage
- 3: Reticulin (Fibrils from fibres around muscle and nerve cells)
- 4: Unique form only found in basal lamina of basement membrane
96
What does elastic fibres consist of?
- Elastin
| - Fibrillin
97
What is the role of white adipose?
- Contains fat as a fuel reserve
- Thermal insulation
- Shock absorption
98
What are the two forms of bone?
- Cancellous (Spongey)
| - Compact
99
What is cancellous bone and where is it found?
- Network of fine bony columns/plates
- Strong and light
- Spaces filled with bone marrow.
- Epiphyseal areas (head of bones)
100
What is compact bone?
- Forms the external surfaces of bones
| - 80% of body's skeletal mass
101
What is the difference between immature and mature bone?
- Immature: osteocytes are randomly arranged
| - Mature: osteocytes are arranged in concentric lamellae of osteons
102
Which type of bone contains Haversian and Volksmann 's canals?
- Spongey
- Compact
- Both
- Compact
103
Outline how new bone is formed.
- Osteoblast surrounds new osteoid and therefore an osteocyte
- Osteoblast moves from lumen to epithelium, deposits new osteoid and therefore new bone.
104
How is a bone remodelled?
- Cutting cone is formed by boring a tunnel through the bone by osteoclasts releasing H+ and lysosomal enzymes.
- Osteoblasts deposit new osteoids.
105
What is endochondral ossification?
- Replacement of a pre-existing hyaline cartilage template by bone,
(How most bones are formed)
106
How is hyaline cartilage transformed into bone?
- Mineralised
107
Outline the formation of bone from Embryo to mature adult.
- Embryo 5-6 weeks: Purely hyaline cartilage.
- Embryo 6-8 weeks: Collar of compact bone appears in shaft.
- Fetus 8-12 weeks: Central cartilage calcifies, Nutrient artery penetrates supplying osteogenic cells, primary ossification centre forms
- Postnatal: Medulla changes to spongey bone & forms epiphyseal growth plates, epiphyses develop secondary ossification centres.
- Prepubertal: Epiphyses ossify and growth plates continue to move apart = lengthening of bone.
- Mature adult: Growth plates replaced by hyaline articular cartilage plates.
108
Name the zones of epiphyseal growth plates from top to base.
- Reserve cartilage
- Proliferation
- Hypertrophy
- Calcified cartilage
- Reabsorption
109
Outline how growth plates induce growth.
- Cells actively divide into columns
- Enlargement, matrix compressed into linear bands between cell columns
- Enlarged cells degenerate and matrix calcifies
- Calcification
110
What is intramembraneous ossification?
- Within condensations of mesenchymal tissue, not by replacement of a pre-existing hyaline cartilage template.
- Thickening not lengthening of bones.
111
Where does intramembraneous ossification occur?
- Flat bones:
- Skull bones
- Maxilla
- Mandible
- Pelvis
- Clavicle
112
What is oesteogenesis imperfecta, and what are the clinical signs?
- Disorders if connective tissue.
- Affects: skeleton, joints, ears, ligaments, teeth, sclerae and skin
- Bowing of bones, easily fractured with limited physical stress, very thin bones.
113
Where is growth hormone synthesised and stored?
Anterior pituitary gland.
114
What are the conditions associated with excessive/insufficient GH during development?
- Excessive: Gigantism via promotion of epiphyseal growth plate activity
- Insufficient: pituitary dwarfism
115
What signs are there of excessive GH in adults?
- Increase of bone width by promoting compact bone growth.
116
What are the main sex hormones in males & females
- Males: Androgens
| - Females: Oestrogen
117
What is the effect early sex hormone production has?
| And for later sex hormone production?
- Retards bone growth due to premature closure (fusion) of epiphyses
- Prolonged bone growth, epiphyseal plates persist in later life.
118
- What conditions do infants with THD (Thyroid hormone deficiency) have?
- Permanent neurological & intellectual damage
| - Short stature
119
What is osteoporosis?
- Incomplete filling of osteoclast resorption bays.
- Mineralised bone is decreased in mass, no longer provides adequate support.
- More susceptible to fracture.
120
What are the risk factors associated with osteoporosis?
- Genetic, peak bone mass is higher in black people
- Insufficient Ca intake
- Insufficient Ca absorption and Vit D
- Exercise
- Smoking
121
How does Achondroplasia occur?
- Decreased endochondral ossification
- Inhibited proliferation of chondrocytes in growth plate cartilage
- Decreased cellular hypertrophy
- Decreased cartilage matrix production
122
What is Achondroplasia?
- Common form of short limbed disease (trunk normal)
| - Normal mentation, average lifespan.
123
What is rickets?
- Childhood disease, bones don't harden due to Vit D deficiency.
- Insufficient Ca deposition for adequate bone rigidity
- Bones are soft and malformed
- Distortion of skull bone
- Enlargement of costochondrial junctions of ribs.
124
What is Osteomalacia?
| What are the symptoms?
- Adult version of rickets
- Due to severe Ca deficiency or lack Vit D
- Bone pain, back ache, muscle weakness.
169
What is the peripheral blood count for the following:
- 1) Hb
- 2) RBC
- 3) WBC
- 4) Platelets
- Hb: 130-160 g/l
- RBC: 4.4-5.5x10^12 g/l
- WBC: 7-11x10^9 g/l
- Platelets: 150-400x10^9 g/l
170
What is the RBC's function?
- Delivery of O2 to tissues
- Carries haemoglobin
- Maintain haemoglobin in reduced state
- Maintain osmotic equilibrium
- Generate energy (ATP)
171
What are the characteristics of the structure of RBC?
- Biconcave
- Flexible
- 8 micrometer diameter
172
What is the function of haemoglobin?
- Carries O2 from lungs to tissues
- Carries CO2 between tissues and lungs
- Haem molecule combines reversibly with O2 and CO2
-
173
What are the roles of globin chains in haemoglobin?
- Protect Haem molecule from oxidation
- Confers solubility
- Permits variation in O2 affinity
174
When is erythropoietin produced?
- Reduced pO2 detected in interstitial peritubular cells in kidneys
- Increases production
175
What does erythropoietin do?
- Stimulates maturation and release of RBC from bone marrow.
- Increased Hb
- Increased pO2
- Erythropoietin production falls (product inhibition)
176
Where are platelets produced?
- Megakaryocytes
177
How is platelet production controlled?
- Thrombopoietin
178
What are the functions of platelets?
- Adhesion to connective tissue
- Aggregation with other platelets
- Facilitate clotting by phospholipid membrane
179
How does adhesion occur with platelets?
- Damage to vessel wall
- Exposure of underlying tissues
- Platelets adhere via receptor and form platelet plug.
180
How do platelets help with clotting?
- Activates clotting cascade
- Interacts with clotting factors VII, IX, X
- Fibrin mesh traps platelets and RBC
181
Outline the stages of neutrophil maturation
- Myeloblast
- Promyelocyte
- Myelocyte
- Metamyelocyte
- Band
- Neutrophil
182
What are the roles of monocytes?
- Migration to tissues: macrophages
- Response to inflammation and antigenic stimuli
- Diapedesis to tissues (migration through intact capillary walls to tissues)
183
What do lysosomes contain?
- Lysozyme
- Interleukins
- Chrachidoric acid
- CSF
265
What do the prefixes sarco- and myo- mean?
- Sarco: flesh/muscle
| - Myo: muscle
266
What types of muscle are striated?
- Skeletal
| - Cardiac
267
What type of muscle is non striated?
- Smooth
268
Where are skeletal muscle cells developed?
- Mesoderm
269
What types of skeletal muscle cells are there?
- Red
- White
- Intermediate
270
How do red skeletal muscle cells differ from white skeletal muscle cells in characteristics?
- Red are richer in myoglobin & vascularisation
- Smaller
- Numerous mitochondria
- Fewer neuromuscular junctions
- Poorer in ATP-ase
- Richer in oxidative enzymes
271
What is the function of red skeletal muscle cells?
- Act more slowly than white
- Slow, repetitive and weaker
- Fatigue slowly
272
What is the function of white skeletal muscle cells?
- Act fast and strongly
| - Fatigue quickly
273
What is the bone to muscle connection called?
| What is the bone to bone connection called?
- Tendon
| - Ligament
274
Where is the sarcolemma positioned?
- Between collagen bundles and muscle fibre's myofilaments
275
In muscle fibres what is the A band, I band and H zone?
- A band is areas of myosin (dark)
- I band is areas of actin only (light)
- H zone is areas of just myosin (between actin)
276
When a muscle contracts what happens to the A band, I band and H zone?
- A band remains the same
- I band shortens
- H zone shortens
277
How is the actin, tropomyosin, tropanin complex formed?
- Actin filament forms a helix
- Tropomyosin molecules coil around the actin helix, reinforcing it
- Tropanin complex is attached to each tropomyosin molecule
278
How are myosin filament heads able to join to actin?
- Increase in Ca ions, bind to TnC of tropanin, moves tropomyosin away from actin's binding sites
- Displacement allows for myosin heads to bind.
279
How do myosin filaments cause contractions?
- Myosin cross bridge attaches to actin myofilament,
- Working stroke, myosin head pivots and bends as it pulls on actin filament, slides towards M line,
- New ATP attaches to myosin head, cross bridge detaches,
- ATP -> ADP + Pi, cocking of myosin head occurs.
280
What is a neuromuscular junction and how does it work?
- 'Synapse' between muscle and nerves
- Axon terminal contains vesicles of acetylcholine (AcH)
- Nerve impulse causes release of AcH
- AcH binds to receptors on sarcolemma
- Na channels open
- Na depolarises muscle causing a Ca release from SR hence muscle contraction
281
What's an epimysium and a perimysium?
- Epimysium: Outer layer of connective tissue lining the fibre as a whole
- Perimysium: Outer layer of individual fibre bundles.
282
Name some recognisable characteristics of cardiac muscle.
- Striations
- 1 or 2 centrally positioned nuclei per cell
- Intercalated discs (electrical & mechanical coupling with adjacent cells)
- Branching
- Endomysium provides a rich blood supply (around individual fibres)
283
In what orientation do T tubules of cardiac muscle lie?
- 'Around' the fibre, i.e in register with Z bands, not with A-I band junction.
284
What are the cells called that carry impulses across the heart?
- Purkinje fibres, distal conducting cells.
285
What are the characteristics of Purkinje fibres?
- Abundant in glycogen
- Sparse myofilaments
- Extensive gap junction sites.
- Conducts rapidly, enables ventricles to contract synchronised.
286
What shape are smooth muscle cells?
- Fusiform (spindle shaped with a central nucleus)
287
True or false? (Smooth muscles)
- Striated
- No sarcomeres
- No T tubules
- Contraction still relies on actin-myosin interactions
- Contraction is rapid and requires lots of ATP
- Can only remain contracted for short periods of time
- Can be stretched
- False
- True
- True
- True
- False
- False
- True
288
How are smooth muscles stimulated?
- Nerve signals
- Hormones
- Drugs
- Local concentrations of blood gases
289
How does smooth muscle look?
- Sheets
- Bundles
- Layers
290
Where is smooth muscle commonly found and what is its primary role?
- Vascular structures' walls
- GI
- Respiratory tract
- Genitourinary system
- Modifies volume
291
In what conditions would smooth muscle have a clinical significance?
- Asthma
- High bp
- Atherosclerosis
- Abnormal GI mobility
292
What are myoepithelial cells and their roles?
- Basketwork around secretory units of exocrine glands
- Contraction assists secretion
- Dilation of pupil in iris
293
What are the roles of myofibroblasts?
- Sites of wound healing,
- Produce collagenous matrix
- Wound contraction
- Tooth eruption
294
How do smooth muscles contract?
- Thick and thin filaments are arranged diagonally, spiralling down long axis
- Contracts in a twisting way
295
Can skeletal muscles repair?
- Yes
- Mitotic activity of satellite cells (hyperplasia) after an injury
- Satellites can fuse to existing muscle cells to increase mass
296
Can cardiac muscles repair?
- No
| - Fibroblasts cause scar tissue
297
Can smooth muscle repair?
- Yes
| - Mitotic activity
298
What is atrophy?
- Destruction -> replacement
| - Muscle wastage
299
What is hypertrophy?
- Replacement -> destruction
- Muscle size increase
- More contractile proteins hence increase in fibre diameter
- Metabolic changes: increase: enzyme activity for glycolysis, mitochondria, stored glycogen, blood flow
300
What is disuse atrophy?
- Loss of protein
- Reduced fibre diameter
- Loss of power
301
What is denervation atrophy?
- Signs of lower motor neurone lesions:
- Weakness, flaccidity, muscle atrophy
- Re-innervation within 3 months for recovery
302
How is an action potential terminated?
- Acetylcholinesterase
303
What is myasthenia gravis?
- Autoimmune destruction of end-plate & ACh receptors
- Loss of junctional folds
- Widening of synoptic cleft
304
What are the symptoms and treatment of myasthenia gravis?
- Fatigue and sudden falling (reduced ACH release)
- Drooping eyelids, blurred vision
- Affected by state of health and emotion
- Acetylcholinesterase inhibitors
305
- Duchenno and Becker are types of what and what are they?
- Genetic muscular dystrophies
- Duchenno: absence of dystrophin
- Becker: Deficiency of dystrophin
306
What is DMD?
- Protein abnormality
- Muscle fibres tear themselves apart on contraction
- Pseudohypertrophy (swelling) occurs before fat and connective tissue can replace muscle fibres
- Contractures (imbalance between agonist and antagonist muscles)
307
What treatment is there for DMD?
- Steroid therapy
| - Genetic research
308
Give 5 examples of myopathies.
- Inflammatory
- Electrolyte imbalances
- Thyrotoxicosis
- Hypoparathyroidism
- Channelopathies
309
What is haemopoiesis?
- Formation of blood cellular components.
310
What are the peripheral blood counts for:
| Hb, RBC, WBC & Platelets?
- Hb: 130-160g/L
- RBC: 4.4-5.5x10^12/L
- WBC: 7-11x10^9/L
- Platelets: 150-400x10^9/L
311
What is the MCV function values?
- 80-100 fl
| - (Mean corpuscular volume)
312
What is the function of RBC?
- Delivery of O2 to tissues
- Carries haemoglobin
- Maintain haemoglobin in reduced state
- Maintain osmotic eqm
- Generate energy (ATP)
313
What are the physical characteristics of RBC?
- Biconcave, flexible disc 8micrometer diameter
| - Microcirculation minimum diameter 3.5micrometer.
314
What is the function of haemoglobin?
- Carries O2 from lungs to tissues
- Carries CO2 between tissues and lungs
- Haem molecule combines reversibly with O2 and CO2
- Globin chains: Protect Haem molecule from oxidation
Confer solubility
Permits variation in O2 affinity
315
What is the role of Erythopoietin?
- Reduced pO2 detected in interstitial peritubular cells in kidneys
- Increase production of Erythropoietin
- Erythropoietin stimulates maturation and release of RBC from marrow
- Hb increase
- pO2 increase
- Erythropoietin production falls.
316
How are platelets produced and what hormone controls this?
- Megakaryocytes produce platelets
- Cells increase in size and replicates DNA
- Platelets 'bud' from cytoplasm
- Controlled by Thrombopoietin
317
What is the function of platelets?
- Adhesion to connective tissue
- Aggregation with other platelets
- Phospholipid membrane to facilitate clotting
318
How does adhesion occur with platelets?
- Damage to vessel wall
- Exposure of underlying tissues
- Platelets adhere via vWF/receptor and form platelet 'plug'.
319
What role does platelets have in clotting?
- Fibrin mesh formed by clotting factors
| - Traps platelets and RBC.
320
How does neutrophil maturation occur?
- Myeloblast -> Promyelocyte -> Myelocyte -> Metamyelocyte -> Band -> Neutrophil
321
What is the role of monocytes?
- When migrate to tissues they become macrophages
- Response to inflammation and antigenic stimuli
- Diapedesis to tissues
322
What is the contents of lysosomes?
- Lysozyme
- Complement
- Interleukins
- Crachiadoric acid
- CSF
323
What is the RES?
- Reticuloendothelial system
- Immune system containing Phagocytic cells
- RES cells identify and mount an appropriate immune response to foreign antigens
- Main organs: Spleen, Liver, lymph nodes
- ECF travels via lymphatic to LN.
324
What are the roles of eosinophils?
- To mediate hypersensitivity reactions
| - e.g asthma/skin inflammation
325
What are basophils?
- Dense granules
| - Active in allergic reactions
326
What are Beta cells' functions?
- Express antigen specific Ig
- T cell interaction transforming to plasmablasts/memory cells within lymph nodes.
- Plasmablasts migrate to marrow and form plasma cells (Ig production)
327
What are T cells functions?
- Migrate to thymus and undergo TCR arrangement
- Differentiate into helper and suppressor
- Helper cells induce proliferate and differentiation of T&B cells active macrophages
- Suppressor has cytotoxic activity and induces apoptosis
328
What are natural killer cells?
- Recognise self
| - Kill non self cell lines by lysis.
329
What is the innate immune response?
- Inbuilt immunity to resist infection
- Natural immunity, present from birth
- No memory
- Not specific
- Not enhanced by secondary exposure
- Uses cellular and humoral response.
330
What is the adaptive immune response?
- Immunity established to adapt to infection
- Specific or acquired immunity
- Learnt by experience
- Confers to pathogen specific immunity
- Enhanced to secondary immunity
- Memory
- Cellular and hormonal response
331
How does the body facilitate the removal of pathogens from the body? Give 5 examples.
- Blinking
- Coughing
- Sneezing
- Mucociliary escalator
- Vomiting
- Digestive enzymes.
332
What is the role of inflammation mediators?
- inflammation mediators increase the permeability of blood vessels at the site of infection to allow:
- Release of antibodies, macrophages, neutrophils and lymphocytes.
333
What are the cells involved with innate immunity?
- Macrophages/monocytes: Phagocytosis/presentation to lymphocytes
- Neutrophil/PMN: Phagocytic/antibacterial
- Eosinophils: Anti-parasite
- Basophils
- Mast cells: protection of mucosal surfaces/allergy
334
What is phagocytosis?
- Active engulfment of particles into phagosomes.
335
What are phagosomes?
- Macrophages and neutrophils
| - Those with the ability to destroy bacteria/extracellular viruses/immune complexes
336
What are the roles of neutrophils?
- Work best in anaerobic conditions which prevail in damaged tissue
- Initiates inflammation.
337
What is the role of macrophages?
- Phagocytose microbial cells, damaged/unwanted cells
- Release cytokines important in both types of immunity
- Can generate lysosomes when needed.
338
What do natural killer cells do?
- Directly induce apoptosis in virus cells by pumping in proteases
- Recognise and kill abnormal cells such as tumour cells.
339
What is opsonisation?
- The coating of a microorganism in antibodies/complement to make it recognisable as foreign to phagocytes
340
What is the complement system?
- Marking pathogens for destruction by covalently binding to their surface.
341
What are the different stages of the adaptive immune system?
- Recognition phase: Clonal selection and expansion, differentiation to effector cells
- Activation phase
- Effector phase: Elimination of pathogen
- Decline homeostasis: apoptosis of T and B cells
- Memory
342
What are the 4 membranous layers protecting the brain?
- Skull
- Dura mater
- Arachnoid mater
- Pia mater
343
What are the meninges?
- Dura mater
- Arachnoid mater
- Pia mater
344
What is the leptomeninges?
- Dura mater and arachnoid mater together.
345
What is the epineurium?
- Sheaths for a whole nerve
| - Interfascicular bands join adjacent nerve fascicles.
346
What is the perineurium?
- Sheaths a nerve fascicle.
| - A fascicle is a group of axons.
347
What is the endoneurium?
- Sheaths individual axons
348
What are the two types of nerve cells and how is it split?
- Glia: 90%
| - Neurone: 10%
349
What are dendrites?
- Specialisations of cell bodies
| - Main role is to increase surface area of cell body.
350
What is the difference between temporal and spatial summation?
- Temporal summation: Summated with respect to time of arrival.
- Spatial summation: Summated with respect to their location
351
What is the function of an axon?
- Summates all inputs to the neurone
- Initiates action potentials & therefore neurotransmitter production
- Communicates with follower cell
352
How are neurotransmitters released and used as interneural communicators?
- Action potential arrives along axon terminal
- Opening voltage gated Ca channels
- Ca diffuses into synaptic knob
- Ca triggers synaptic vesicles containing neurotransmitters to fuse with presynaptic membrane
- Neurotransmitter diffuses across synaptic cleft and binds to a receptor which in turn is bound to a Na channel
- Na channels allow Na to diffuse into dendrite and create a new action potential
- Acetylcholinease breaks down acetylcholine so no continuous firing of action potentials.
353
What are the three classes of neurone?
- Sensory
- Motor
- Relay/inter.
354
What is the role of a sensory neurone?
- Afferent pathway
| - Receptor to CNS.
355
What is the role of a motor neurone?
- Efferent pathway
| - From brain to muscles
356
What are relay neurones?
- Relay the information between sensory and motor neurones.
