Body Logistics Flashcards
1
Q
What are some methods of measuring temperature?
A
2
Q
What are the temperature ranges for:
- Heat exhaustion.
- Heat stroke.
- Fever.
- Normal.
- Mild hypothermia.
- Severe hypothermia.
and what are the clinical symptoms?
A
3
Q
What are the two buffering systems used in the body, and what are they used for?
A
Carbonic acid - bicarbonate system, used for blood pH maintenance.
Sodium phosphate buffering system, used for intracellular pH.
4
Q
What happens if there is insufficient water in the body?
A
5
Q
What happens if there is too much water in the body, and what can be done clinically?
A
6
Q
What are the 4 classifications of tissue?
A
Muscle.
Nerve.
Connective.
Epithelial.
7
Q
What can enlarged red blood cells, under a microscope, indicate?
A
Vasculitis.
8
Q
What does periodic acid-Schiff stain?
A
Sugars.
9
Q
How does a confocal microscope work?
A
Multiple snapshots are taken in the 3 dimensions and put together.
10
Q
What are confocal microscopy used for in clinical practice?
A
Evaluation of eye diseases.
11
Q
How are living cells prepared?
A
12
Q
What are morphogenesis and differentiation?
A
Mophogenesis = development of form and structure.
Differentiation = specialisation for function.
13
Q
What is the timeline of the pre-embryonic, to embryonic to fetal development?
A
Pre-embryonic = first 2 weeks.
Embryonic = weeks 3-8.
Fetal = weeks 9-38.
NOTE: remember to add the first 2 weeks from the last menstrual period.
14
Q
Where is the oocyte usually fertilised?
A
Ampulla, where it becomes the zygote.
15
Q
What is the zona pellucida?
A
Glycoprotein shell, encasing the (totipotent) morula.
Prevents the further fertilisation of more sperm.
16
Q
What is PGD (Pre-implantation Genetic Diagnosis) and what is it used in?
A
Where one cell from the morula is removed and tested for serious inheritable diseases.
It is used in IVF treatment.
17
Q
What are the resultant structures after compaction?
A
The zona pellucida encases the trophoblasts.
The embryoblasts are a mass, attached to the trophoblasts.
The space within the trophoblasts is called the blastocoele.
18
Q
What are totipotent and pluripotent stem cells? Give an example.
A
Totipotent can divide into any type of cells, such as blastomeres (cells of the morula).
Pluripotent can divide into many types of cells, such as embryoblasts.
19
Q
What needs to occur before the blastocyst can interact with the uterine surface? When does this occur?
A
Hatching from the zona pellucida.
Between day 5 and 6.
20
Q
What occurs in implantation?
A
The fibrin plug closes, which can cause bleeding.
A maternal blood flow through the placenta is established.
21
Q
What type of blood vessels invade the syncytiotrophoblasts?
A
Sinusoids.
22
Q
How does the neural tube form, during neurulation? What does it give rise to?
A
The notochord signals the overlying ectoderm to thicken and form the neural plate.
The neural plate then curls towards each other, until they reach, forming the neural tube.
These give rise to the brain and spinal cord.
23
Q
What are somites made of? What does each component become?
A
Sclerotome and dermatomyotome.
The sclerotome becomes the bone.
Dermatome becomes the innervated area of the dermis of skin.
Myotome becomes the innervated muscles.
24
Q
Where are the cilia that control the flow of signalling molecules during embryology located?
A
Primitive node - the signals are sent by the primitive streak.
25
Where are tight junctions located, and what is their function?
Apical, between the two epithelial cells.
They can transiently open to allow molecules to reach the deeper layers of the organ, through paracellular transport.
26
What are adhesion junctions formed from, and what are they linked to?
Formed from actin filaments and linked to E-cadherins.
27
What is the only cell-to-cell adhesion found in the upper epidermal layer?
Desmosomes, to provide mechanical strength and prevent tissue destruction.
28
What do hemi-desmosomes attach?
Extracellular matrix laminin of the basal lamina to the intermediate filaments of cytokeratin within the cell, through integrins.
29
What do focal adhesions attach?
Extracellular matrix fibronectin of the basal lamina to the actin filaments within the cell, through integrins.
30
When are integrins at their strongest?
When two dimers come together via phosphorylation.
31
What are the layers of the basement membrane?
Basal lamina - contains two layers, the lamina lucida which is clear, and the lamina denser which is dense.
Reticular layer - very dense layer containing lots of collagen.
32
What do adhesion proteins require to function?
Calcium ions.
33
What does mucous contain?
Mucin proteins, electrolytes, water, lysozyme (antiseptic enzymes) and immunoglobulins.
34
What are the 5 layers of the GI tract, from inside to out?
Mucosa - mucous membrane that projects epithelial cells into the lumen.
Muscularis mucosae - thin smooth muscle layer.
Submucosa - connective tissue layer containing some blood vessels.
Muscularis external - contains an inner circular and an out longitudinal muscle layer.
Serosa - connective tissue layer with some blood vessels and nerve fibres.
35
What specialisations does the GI tract have to aid its functions?
Epithelial cells have microvilli to aid absorption.
Lamina propria contains lymphatic tissue to prevent ingress of pathogens.
Muscularis mucosae has folds to increase the surface area for absorption.
Muscularis external can contract for peristalsis to move contents.
36
What is the structure of the trachea and primary bronchi?
Mucosa - ciliated cells with a thin lamina propria but not longitudinal muscularis mucosa.
Submucosa - connective tissue layer, also contains goblet cells.
C-shaped hyaline cartilage - 2 layers, 1 containing fibroblasts that synthesise collagen and 1 containing chondrocytes that synthesise cartilage.
37
What is the basement membrane formed of?
Basal lamina (lamina lucida and denser) + reticular layer.
38
What is the structure of pseudostratified epithelia?
All cells touch the basement membrane with the nuclei at different heights. Not all cells reach the epithelial surface.
The basement membrane undulates as the cells try and pull it up to reach the surface.
39
What is the mucociliary escalator?
The production of mucous in combination with ciliated cells.
The mucous traps dirt and pathogens and the cilia waft it towards the mouth where it can be swallowed and digested or spat out.
40
How are goblet cells specialised and how do they release their products?
They have microvilli on the apical surface.
They release mucin in vesicles through exocytosis.
41
What gene is mutated in cystic fibrosis, and what can be the complications of it, e.g., airway, liver, pancreas, small intestine, reproductive system, skin?
The CFTR gene - can’t release sufficient Cl- ions so sticky mucous.
42
What is stratified squamous epithelia, and how are the cells held together?
It is multiple layers of cells, with the outermost being squamous epithelia.
They’re held together by desmosomes.
43
How does early stage smoking damage the lungs?
Normal mucous layer thickens.
Cilia die off and take 2-4 days to regenerate.
44
How does chronic stage smoking damage the lungs?
Goblet and basal cells proliferate, leading to excess mucous.
Club cells metaplaise or die.
Carcinogens can act as initiators and cause mutations for cancer.
Pneumocytes die and fibroblasts lay down scar tissue, decreasing the ability for gas exchange.
45
How does branching and elongation of exocrine glands occur?
FGF10 is secreted by immature fibroblasts and epithelial cells grow towards the signal by:
- Elongation, stimulated by growth factor 1.
- Branching, stimulated by growth factor 2.
They occur one after another, never at the same time.
46
State the 7 types of gland shape and an example for each.
Simple tubular - intestinal glands.
Simple branched tubular - stomach glands.
Compound tubular - duodenal glands.
Simple alveolar - foetal glands.
Simple branched alveolar - sebaceous glands.
Compound alveolar - mammary glands.
Compound tubuloalveolar gland - salivary.
47
Define the terms:
- Striated.
- Demilune.
- Intercalating.
- Acinar.
All relating to glands.
Straited = striped.
Demilune = half-moon.
Intercalating = between two glands.
Acinar = sac-like.
48
How do the glands of the breasts develop?
Oestrogen and progesterone during puberty, and prolactin during pregnancy, that all stimulate the growth of the glands.
49
What is a cytocrine, merocrine, apocrine, and holocrine gland?
Cytocrine - whole cells are released.
Merocrine - a form of exocytosis.
Apocrine - partial loss of cytoplasm.
Holocrine - whole loss of cytoplasm.
50
How does merocrine secretion occur?
Vesicles are stimulated to move via Ca2+ ions.
They move along microtubules.
The vesicle fuses to the cell membrane and the contents are released.
51
What are the different methods of transepithelial transport?
Paracellular transport - between cells.
Transcellular transport - lipid-soluble molecules that can diffuse through the membranes.
Carrier proteins.
Endocytosis, followed by exocytosis - transcytosis.
52
What are the different types of hormones, their methods of:
- synthesis and storage.
- transport in the blood.
- location of receptor.
- response to the binding of receptor.
- examples.
53
What do the pituitary, thyroid, parathyroid, pancreas and adrenal glands develop from in embryology?
Pituitary - hypophyseal pouch and neurohypohpyseal bud.
Thyroid - the floor of the pharynx.
Parathyroid - pharyngeal pouches.
Pancreas - foregut.
Adrenal - intermediate mesoderm and neural crest.
54
What are all the pituitary hormones secretion methods?
Constitutive or regulated merocrine secretions.
55
What type of cells are parafollicular cells, what do they release, and what are the effects of it?
They are neuroendocrine cells of the thyroid.
They release calcitonin.
Calcitonin inhibits osteoclast function and decrease the (re-)absorption of calcium to decrease the plasma levels.
56
What is the definition of a stress response?
The response to a perceived or real threat to homeostasis.
57
What is the structure of the serous pancreatic glands, and how are the ducts connected?
They are acinar glands that are grouped into lobules, containing zymogens.
They are connected through intercalated ducts to the pancreatic duct, which joins the bile duct to make the common bile duct.
58
Why do goblet cells appear white with H&E staining?
They contain sugars which does not stain with H&E.
59
What types of glands are blocked with inflammation of the parotid gland?
Striated ducts.
60
What is the pattern of gland accumulation to secretion?
Intralobular duct - inside the lobule.
Intercalated duct - between 2 lobules.
Striated duct - accumulation of intercalated ducts, they’re stripy.
Excretory duct - striated ducts come together.
Main collecting duct - multiple excretory ducts come together and products are secreted onto the surface.
61
What is the function of striated ducts?
To prevent water loss.
62
What are the 3 types of capillary vessels, describe them and where are they found?
Continuous, intact basement membrane with small intercellular clefts - brain and most of the body.
Fenestrated, intact basement membrane with small fenestrations in the endothelium - kidney, pituitary, small intestine, and around some endocrine glands.
Sinusoid, incomplete basement membrane and large intercellular gaps - spleen, liver, bone marrow and lymph nodes.
63
How many nuclei do liver cells have?
2 or 3.
64
Explain the route of bile from the liver to gall bladder.
Bile canaliculi between the hepatocytes.
Interlobular tributaries in the duct/ periportal bile ductules in the triads (same but different name).
Bile duct.
Left and right hepatic ducts.
65
Where do Ito/ stellate cells hold the vitamin A, and what can they differentiate into in liver cirrhosis?
The vitamin A is held in vacuoles.
They can lose their vitamin A storage and differentiate into fibroblasts.
66
Describe the organelles of hepatocytes.
Numerous mitochondria.
Extensive Golgi and endoplasmic reticulum (R and S).
Lots of free ribosomes.
Glycogen deposits.
67
Describe the regeneration ability of the liver, depending on the extent of damage, and its recovery time.
Less than 50% damage, due to viral infection or occasional alcohol use will regenerate in around 7-8 days.
50-70% damage, due to heavy alcohol use, drug toxicity or liver transplant, will regenerate in around 30-40 days.
Over 70% damage, wide to chronic alcohol misuse, suicide attempts and cirrhosis, leads to liver failure and will never regenerate.
68
Explain the storage function of the liver.
69
Explain the anabolic function of the liver.
70
Explain the catabolic function of the liver.
71
What are some other functions of the liver?
Bile production - its exocrine function.
Filtering debris from the blood.
Hormone and growth factor production - endocrine function.
Modifying hormones, such as thyroxine to T3.
72
What is extracellular matrix?
Ground substance and fibres.
73
What are the 3 substances that are held in mast cell granules?
Histamine - increase blood vessel wall permeability.
Heparin - anticoagulant.
Cytokines - attract neutrophils and eosinophils.
74
What is ground substance, and what is its function?
It is a clear, viscous and slippery substance with a high water content.
It contains proteoglycans - core protein with glycosaminoglycans covalently bound.
GAGs are hydrophilic and attract more water.
This allows for rapid diffusion and high compression resistance.
75
What are the symptoms of scurvy?
Bleeding - poor wound healing.
Tooth loss.
Bruising of the skin and hair loss.
Weakness and fatigue.
Impaired bone development in the young.
76
What are some symptoms of Marfan’s syndrome?
Excessively tall.
Arachondactyly - spider-like fingers and toes.
Frequent joint dislocation.
Aortic rapture.
77
What is the structure of elastin fibres and where is it found?
It is elastin surrounded by fibrillin.
It is found in the dermis of the skin, in artery walls, in the lungs and in elastic cartilage.
78
In the aorta, what is it that produces the elastin, collagen and matrix?
The smooth muscle cells.
79
What are the terms for myoglobin in the blood and urine?
Blood = myoglobinaemia.
Urine = myoglobinuria.
80
What are the names for the plasma membrane, cytoplasm, mitochondria, functional unit and SER of a muscle cell?
81
What are the dark and light striations of a muscle cell - what is the line in the middle of the light band?
Dark = A band.
Light = I band.
Line in the middle of the light band = Z band.
82
What is a motor unit?
A motor neurone and the muscle fibres it innervates.
83
What is the function of smooth muscle that surrounds passageways or cavities?
To modify the volume.
84
Which cell type undergoes hyperplasia following skeletal muscle injury?
Satellite cells - they can also fuse with existing muscle cells to increase mass: hypertrophy.
85
What are the thick filaments made of?
Multiple myosin molecules.
86
What are the two components of actin?
F-actin fibres.
G-actin globules.
87
What forms the thin filament of skeletal muscles?
Actin, tropomyosin and toponins.
88
Outline the re-training cycle.
89
What cells do new muscle fibres arise from?
Mesenchymal stem cells.
90
What is malignant hyperthermia a defect in, and what is its inheritance pattern?
Defect in the RyR1 gene.
It is autosomal dominant, but is seen more often in men than women.
91
What do the terms osteogenesis, osteomyelitis, osteopathy, osteoporosis, and osteosarcoma mean?
Osteogenesis = formation of bone.
Osteomyelitis = infection within bone.
Osteopathy = disease of the bone.
Osteoporosis = weakness of bone.
Osteosarcoma = primary bone cancer.
92
What are the two sections of the skeleton and how many bones are in each?
Axial = 80 bones.
Appendicular = 126 bones.
93
What is endochondral ossification/ appositional bone growth?
It is growth from within cartilage.
It is continued lengthening by ossification from epiphyseal growth plates.
They develop into long bones.
94
What is intra-membranous ossification/ interstitial growth?
It is the formation of bone from the centre of the bone.
The mesenchymal stem cells differentiate and help form the new bone.
They develop into flat bones.
95
How does intra-membranous ossification occur?
Through ossifications at the centre of the bone, mineral deposits are laid down and radiate outward from the osteoblasts - differentiated mesenchymal stem cells.
96
What molecule mineralises osteoid?
Hydroxyapatite - a molecule composed mainly of calcium and phosphate.
97
What is the difference in structure between osteoblasts and osteoclasts?
Osteoblasts are mononucleated.
Osteoclasts are multinucleated.
98
What do MSCs do in the formation of bone?
Differentiate into osteoblasts to lay down osteoid.
Differentiate into blood vessels, lymph vessels and nerves.
99
What do osteocytes reside in and how do they receive their nutrients?
They reside in lacuna and give cytoplasmic projections in the form of filopodia - cytoplasmic projections that allow for communication between osteocytes.
100
What are the cutting and closing cones?
Cutting cone = osteoclasts widen the tunnel between cortical bone.
Closing cone = osteoblasts make a smaller tunnel of cortical bone.
101
What is osteoid made up from?
90% collagen, 10% ground substance.
102
How does calcitonin decrease osteoclast activity?
It blocks the action of PTH at the PTH receptor.
103
What can osteomalacia be caused by?
Kidney disease - cannot activate vitamin D.
Little sunlight - little vitamin D activated.
Stomach or intestine surgery - little absorption of calcium.
Drugs.
104
Where are osteoblasts, osteoclasts and osteocytes found in cortical and spongy bone?
Cortical bone = osteoblasts and osteoclasts on the surfaces, and osteocytes in the concentric lamella.
Spongy = osteocytes in the irregular lamella, and osteoclasts on the surface.
105
What do sinusoidal cells have on their membranes?
Aquaporins and glycophorins (holds cell in place).
106
What is the flow of blood through the capillaries controlled by?
Pre-capillary sphincters and arterioles.
107
What are the 3 layers of a vein?
Tunica intima - endothelial cells.
Tunica media - elastic fibres and smooth muscle cells.
Tunica adventitia - elastic fibrous capsule.
108
What are valves made out of?
Fibroelastic cartilage.
109
What are the 3 main layers of an artery? What are the other 2 layers?
Tunica intima - elastic membrane, lined with endothelium.
Tunica media - composed of smooth muscle and elastic fibres with two distinct layers.
Tunic adventitia - composed of collagen and elastic fibres, allowing arteries to stretch.
Internal elastic membrane (between intima and media) and external elastic membrane (between media and adventitia).
110
What are collateral blood vessels also called?
Communicating blood vessels - provide an alternative pathway for arterial blood.
111
What are the first steps of angiogenesis before the type is decided?
VEGF, produced by the endoderm, generates the primary plexus.
The primary plexus folds into a primary vessel.
112
What are the two types of angiogenesis?
Sprouting:
- FGF produced by mesenchymal cells.
- Pericytes convert into smooth muscle cells.
- Slow, taking hours to days.
Interssusception:
- The primary vessel splits into two.
- Multiple growth factors are needed.
- Quick, taking minutes to hours.
113
How is an X-ray produced?
A wire in an X-ray tube is superheated and electrons are accelerated towards a metal target.
The metal target then produces X-rays/ photons that are sent towards an X-ray detector.
The X-rays are digitised and processed to produce an image.
114
What is the systematic interpretations of abdominal X-rays?
ABDO:
- Air.
- Bowel.
- Densities - bones, stones, tubes, foreign bodies.
- Organs.
115
What can X-rays be used to help diagnose with in the chest, abdomen and MSK?
Chest = infections, pulmonary oedema, pleural effusion, pneumothorax, cancer.
Abdomen = obstructions, perforation, abdominal aortic aneurysm.
MSK = fractures, dislocations, tumours.
116
What are some good contrasts used for fluoroscopy, and why are they used?
Barium or iodine - they are dense and so they attenuate the X-ray pulses, allowing motion and function to be seen.
117
What can fluoroscopy be used to help in vasculature, GI, and MSK?
Vasculature = thrombi, the vasculature itself, angioplasty and stenting.
GI = barium swallow to see blockages and movement of food.
MSK = therapeutic joint injections, orthopaedic surgery.
118
What can CTs be used for?
Trauma, bleeding, complex fractures, cancer, obstructions, perforations, etc.
119
What is a radiopharmaceutical? What is an example?
A compound that is taken up by the tissue of interest and sends out gamma rays to be detected by a gamma camera.
18F-FDG - radioactive glucose analogue.
120
How many days of radiation is a:
- Chest X-ray.
- Abdominal X-ray.
- CT head.
- Barium meal.
- CT chest.
- CT abdo.
C-X-RAY = 3 days.
Abdominal X-ray = 4 months.
CT head = 1 year.
Barium meal = 1 year.
CT chest = 3.5 years.
CT abdo = 4.5 years.
121
How are MRI images created?
Strong magnets align the hydrogen atoms of water molecules within the body.
A strong radiofrequency pulse is applied, which knocks the hydrogen atoms out of alignment.
The pulse ends and the hydrogen atoms realign, emitting energy.
This energy is taken in and processed by a computer to create an image.
122
How are ultrasound images created?
Crystals in the probe oscillates, creating high frequency sound waves.
Sound waves are emitted, travel through tissues and are reflected back by high density tissues.
Probe detects the sound waves and converts them into electrical signals for a live image to be formed.
123
What does the time and proportion of waves reflected show?
The time allows a position of where the tissue is to be formed.
The greater the proportion of waves reflected back, the greater the density, the whiter the image.
124
What is acoustic shadowing?
Sound waves that are completely reflected back, leading to an area of black past that point. It can be due to:
- Bone.
- Air.
- Stones.
125
What is the Doppler ultrasound effect?
The movement of a substance affects the frequency of the sound wave:
- Moving towards the sound wave will give a higher frequency.
- Moving away from the sound wave will give a lower frequency.
126
What are chrondrocytes in clusters called and what causes them to separate? Where do they reside after that?
Isogenous groups, the chondrocytes separate as they lay down extracellular matrix.
After they have separated, they reside in lacuna.
127
What is perichondrium, where is it located in respect to different types of cartilage, and what does it do?
It is dense connective tissue, made up of type I collagen and stem cells.
It is found on both sides of the hyaline cartilage, on the outside of elastic cartilage and not present in fibrocartilage.
It increases the size of the cartilage from the periphery (appositional growth).
128
What is the appearance, location and function of the 3 types of cartilage?
129
What are the 5 different zones of epiphyseal growth plates?
1) zone of reserve cartilage - no cellular proliferation or active matrix production.
2) zone of proliferation - cells divide into columns, and secrete matrix.
3) zone of hypertrophy - cells enlarge, compressing the matrix between the cell columns.
4) zone of calcified cartilage - cells degenerate and matrix calcifies.
5) zone of resorption - chondrocytes die and osteoclasts degrade the cartilage, converting type II collagen to type I and mineralising it.
130
What 3 major body sections makes up the trunk?
Thorax, abdomen and pelvis.
131
Which embryological terms can be used for anterior, posterior, superior and inferior?
Anterior = ventral.
Posterior = dorsal.
Superior = cranial.
Inferior = caudal.
132
What movements occur in the sagittal plane?
Flexion and extension.
133
What movements occur in the coronal plane?
Adduction and abduction.
134
What movements occur in the transverse plane?
Medial and lateral rotation.
135
What movements of the thumb occur in the coronal plane, and why does this happen?
Flexion and extension, as the thumb is rotated 90 degrees.
136
What is a contrast agent?
It is a chemical agent administered to the patient for a scan to increase the ability to differentiate between different types of tissue.
It help characterise pathology.
137
How can contrasts be administered?
Intravenously.
Intraarterially.
Orally.
Rectally.
Injected into a cavity.
138
What are positive and negative contrasts?
Positive - contrast that blocks X-rays, such as iodine or barium.
Negative - contrast that does not block X-rays, such as air or CO2.
139
What contrast is used for MRI and ultrasound?
MRI - gadolinium.
Ultrasound - microbubbles.
140
What are the ideal characteristics of a contrast?
It is cheap and easy to obtain.
It is inert.
It is safe.
It has a low osmolality and viscosity.
It is soluble.
It is stable for storage and within the body.
It can be excreted easily.
141
What are idiosyncratic reactions?
They are acute reactions, ones that occur within an hour.
They can be life threatening.
Severe reactions are very rare.
They cannot be explained by any drugs known mechanism and are unpredictable.
142
Who do idiosyncratic reactions occur most in?
They are at higher risk to people who have had previous reactions, those who have asthma and other allergies.
143
What are mild, moderate and severe symptoms of idiosyncratic reactions?
Mild = flushing, itching.
Moderate = bronchospasm, angioedema, laryngeal oedema.
Severe = anaphylaxis, cardiopulmonary arrest.
144
When should iodinated and gadolinium agents not be given? What can occur if they are?
Patients in kidney failure.
Patients with hyperthyroidism.
Iodinated = nephropathy.
Gadolinium = systemic fibrosis.
145
What are non-idiosyncratic reactions, what can they cause?
Delayed reactions - can occur between an hour and a week after administration.
Can cause nausea, vomiting, syncope, metallic taste or sensation of warmth.
146
What embryological layer of the trilaminar disc do each of the epidermis, dermis and hypodermis come from?
Epidermis and dermis from the ectoderm.
Hypodermis from the mesoderm.
147
What is the corium and cutis?
Corium = dermis.
Cutis = epidermis + dermis.
148
How are the cells in the dermis held together, laterally and basal-apically?
Laterally by adherens junctions.
Basal-apically by desmosomes.
149
What type of epithelium is found in the stratum basale, stratum spinousum, stratum granulosum and stratum corneum?
Basale = columnar epithelium.
Spinousum = cuboidal epithelium.
Granulosum = stratified squamous epithelium.
Corneum = stratified keratinised (dead) squamous epithelium.
150
What is synthesised in the stratum basale, stratum spinousum, and stratum granulosum?
Basale = tonofilaments.
Spinousum = lamellar bodies - keratohyalin factories and lipid production.
Granulosum = lamellar granules that assemble keratin fibrils, and tonofibrils - keratin filaments and keratohyalin granules.
151
What are Merkel cells and what do they look like histologically?
They are mechanoreceptors.
They give a ‘halo’ appearance - a cell with a circle round it.
152
What is the origin and insertion of arrector pili muscle?
The origin is from the dermis.
The insertion is into the hair bulb.
153
Where are sebaceous glands found and what mechanism of secretion do they use?
They are found 2/3rds of the way up the hair follicle.
They use holocrine secretion to release sebum.
154
What is the difference between apocrine and eccrine sweat glands?
Eccrine secrete sweat all over the body, directly onto the skin.
Apocrine secrete pheromones onto the hair follicle, half-way up.
155
What are the 7 mechanoreceptor and their functions?
156
What is the rate of nail growth related to?
The length of the phalanx - the longer the phalanx, the faster the rate of nail growth.
157
What is a small lump, less than 5mm called?
Papule.
158
What is a larger lump, greater than 5mm called?
Nodule.
159
What are small watery blisters called?
Vesicle.
160
What are large watery blisters called?
Bulla.
161
What are pus-filled vesicles called?
Pustules.
162
What is redness called?
Erythema.
163
What is a small non-palpable area of discolouration called?
Macule.
164
What is a large non-palpable area of discolouration called?
Patch.
165
What is a palpable flat-topped area of skin, greater than 2cm called?
Plaque.
166
What is a scratch called?
Excoriation.
167
What is a stretch called?
Striation.
168
What is an itch called?
Pruritus.
169
What is thinning of the skin called?
Atrophy.
170
What is a thread vein, superficial to the skin called?
Telangiectasia.
171
What is scaling of the skin called?
Ichthyosis.
172
What is a superficial and deep loss of epidermis called, respectively?
Superficial = erosion.
Deep = ulcer.
173
What is thickening of the skin with exaggerated skin markings called?
Lichenification.
174
What are too much and too little hair referred to as?
Too much = hirsutism.
Too little = alopecia.
175
What are the 5 cardinal signs of inflammation?
Rubor - redness.
Calor - heat.
Tumor - swelling.
Dolor - pain.
Functio laesa - loss of function.
176
What are the features of psoriasis?
Reduced epidermal transit time.
Acanthosis - thickening of the epidermis.
Increased vascularity of the upper dermis.
177
What are some signs and symptoms of psoriasis?
Symptoms = scaly patches on the outside of the joints (elbows, scalp, knees, forehead).
Signs = pitting of the nails, arthritis and deformities of joints - particularly of the DIPs.
178
What are some treatments of psoriasis?
Topical - topical steroids, vitamin D analogues and emollients.
Systemic - cytotoxic drugs, monoclonal antibodies and retinoids.
179
What is eczema?
Dermatitis - inflammation of the skin. It is a chronic skin disease.
180
What are the two types of eczema?
Internal/ atopic - the chronic skin condition.
External - occupation related.
181
What is the atopic triad?
Asthma, hayfever and eczema.
182
What are some triggers for eczema?
Mostly food allergies - milk, egg, peanut, wheat, soy, fish, etc.
It can just develop with other conditions, such as asthma or hay fever.
183
How is eczema treated?
Topical = topical steroids, topical immunosuppressants, emollients.
Systemic = anti-histamines, immunosuppressants.
184
How is vitiligo treated?
Topical steroids.
Cosmetic camouflage.
Sunscreen.
185
What is acne?
A skin condition that affects the sebaceous glands.
186
What are symptoms of acne?
Comedones (spots) that can be:
- Open; skin pigments found in pits.
- Closed; white-heads.
Papules.
Pustules.
Nodules.
Cysts and scars.
187
What nerves make up the peripheral nervous system?
Cranial nerves.
Spinal nerves.
Peripheral nerves.
188
What is the grey matter in the brain referred to as?
Nuclei - within the cortex.
189
What connects the ventral and dorsal horns, and what does it allow for?
Grey commissure - communication between the left and right side of the body.
190
What does the basic reflex arc consist of?
Sensory neuron, sending information through an interneuron, which sends the information back out through the motor neuron to act on an effector.
191
What are the different structures of neurons and where are they found?
Purkinjie - inside the CNS.
Pyramidal - inside the CNS.
Psuedounipolar/ unipolar - found outside the CNS.
Bipolar - found outside the CNS.
NOTE: pre-synaptic neurons are found inside the CNS and post-synaptic neurons are found outside the CNS.
192
What does axo-axonal synapses do?
An axon synapsing onto another axonal synapse, stimulating or inhibiting the axonal function.
193
Outline the 8 steps of neutransmitter synthesis.
The immature vesicles contain enzyme in their membrane that synthesise the neurotransmitter as it travels down the axon.
194
What is the perineurium made of and what is its function?
Made of a specialised connective tissue containing transport proteins.
It maintains the ionic composition, surrounding each fascicle.
195
What is the difference between a Schwann cell and an oligodendrocyte?
Schwann cells are within the PNS, whereas oligodendrocytes are in the CNS.
Oligodendrocytes myelinate multiple axons whereas Schwann cells myelinate only one axon.
Oligodendrocytes are much smaller.
196
What is the most common type of multiple sclerosis?
Remitting and relapsing.
197
What is the cause of Guillain-Barré syndrome?
Damage to myelin in the PNS.
198
How can you determine where damage the the spinal cord is, based off of symptoms?
Dermatome and myotome.
Also based on what kind of symptoms they’re experiencing:
- Sensory only = dorsal root damage.
- Motor only = ventral root.
- Mixture of the 2 = spinal nerve.
199
What is the place where the synapse between two motor neurons called?
The autonomic ganglion.
200
At what levels do the pre-ganglion neurons needs to ascend and descend the chain?
Above T1, they need to ascend - mainly head and neck.
Below L2, they need to descend - mainly lower limbs.
201
Why would the sympathetic pre-ganglionic neurons traverse the chain?
To synapse at pre-aortic ganglion, to get to their abdominal targets via blood vessels.
202
What is the major source of parasympathetic pre-ganglionic input to the thoracic and abdominal viscera?
The vagus nerve - the 10th cranial nerve.
203
How much lymph is recycled from the interstitial fluid each day? What is its pH?
3-5 litres of fluid of around pH 7.4.
204
Where are lymphatic capillaries found?
Around capillary beds, soaking up the interstitial fluid that leaves from them.
205
What is the arrangement of layers of the lymphatic vessels like and how does lymph flow between them?
They can be superficial or deep, with the deep laying deep to the deep fascia.
Lymph flows from superficial to deep.
206
What is lymphangion?
Compression of lymphatic capillaries by local veins and arteries that propels the lymph.
207
What are the left and right venous angles located between?
The left and right subclavian veins and their internal jugular veins.
208
What is the main connective tissue of lymph nodes and what is it made by?
Reticulin - type III collagen.
It is made by reticular cells, which are specialised fibroblasts.
209
Where are follicular dendritic cells located?
In germinal centres of lymph nodes to proliferate B cells by presenting the antigens to T cells, which activate the B cells.
210
Define the term antigen.
A substance that can induce a specific immune response.
211
Describe the difference between B cells and T cells in antigen recognition.
B cells can recognise antigens without the need of antigen presenting cells, unlike T cells.
212
What are the 6 different secondary lymphatic organs?
Lymph node.
Spleen.
Tonsils.
Appendix.
Payer’s patches.
Diffuse lymphatic nodules.
213
What is thymic cell education?
The maturation of bone marrow derived stem cells, into immunocompetent T cells.
214
How does the structure of the thymus compare to lymph nodes, and how does it change over time?
It is fully formed at birth, with a similar structure to lymph nodes but with no hilum. During puberty, it undergoes involution and is replaced with white adipose tissue.
215
What is myasthenia crisis?
Inability to swallow due to wakened muscle.
216
What is the structure of the tonsils, relating to their function?
They are nodules that are fully formed and functional at birth, containing invaginations and micro fold cells to increase the surface area for antigen recognition and for antigen presenting to underlying immune cells.
217
What is the location, structure and function of the vermiform appendix?
218
Where are Payer’s patches located?
Inferior to and attached to the ileum.
