peer teaching Flashcards
1
Q
what are the 2 main causes of V/Q mismatch
A
- ventilated alveoli but lack of blood supply (ie blood clot)
- adequate blood flow but lack of ventilation (ie collapsed alveoli)
2
Q
what is the local homeostatic response to a V/Q mismatch caused by a decrease in ventilation
A
vasoconstriction of vessels so that blood is diverted away from poorly ventilated areas
3
Q
what is the local homeostatic response to a V/Q mismatch caused by a decrease in blood supply
A
bronchoconstriction to areas of poor blood flow so that air is diverted to areas of better blood supply
4
Q
if FEV1 is less than … it is abnormal
A
<80% of expected value
5
Q
if FVC is less than … it is abnormal
A
<80% of expected value
6
Q
define FEV1
A
forced expiratory volume in one second
7
Q
define FVC
A
forced vital capacity - volume of air that can be forcebily exhaled after maximum inspiration
8
Q
what values would indicate airway obstruction
A
FEV1/FVC is below 0.7
9
Q
what values would indicate airway restriction
A
FEV1/FVC is normal but FVC is low (<80%)
10
Q
what are the two parts of the medullary respiratory group
A
dorsal resp group and ventral resp group
11
Q
what is the dorsal respiratory group responsible for
A
- fires during inspiration
- activates muscles involved in inspirationn (diaphragm and external intercostal muscles)
12
Q
what is the ventral respiratory group responsible for
A
- contains the respiratory rhythm generator
- contains pacemaker cells that set the basal resp rate
- contains expiratory neurons that are most important when active expiration occurs
13
Q
what are the two parts of the pontine area involved in respiration and where are they located
A
pneumotaxic centre - upper pons
apneustic centre - lower pons
14
Q
what is the pneumotaxic centre of the pons responsible for
A
smooths the transition between inspiration and expiration
15
Q
what is the apneustic centre of the pons responsible for
A
- fine tunes the output of the inspiratory neurons of the medulla
- continues activating inspiratory neurons to inhibit expiration
16
Q
define: inspiratory reserve volume
A
amount of in excess tidal inspiration that can be inhaled with maximum effort
17
Q
define: expiratory reserve volume
A
amount of air in excess tidal expiration that can be exhaled with maximum effort
18
Q
define: residual volume
A
amount of air remaining in the lungs after maximal expiration
19
Q
define: vital capacity
A
amount of air that can be exhaled with maximum effort after maximum inspiration
20
Q
define: functional residual capacity
A
amount of air remaining in the lungs after a normal tidal expiration
21
Q
define: total lung capacity
A
the maximum amount of air that the lungs can hold
22
Q
define: tidal volume
A
amount of air inhaled or exhaled in a normal breath (500ml)
23
Q
what is Dalton’s law
A
pressure exerted by each gas in a mixture of gases is independent of the pressure exerted by other gases
24
Q
what is Boyle’s law
A
pressure of a fixed amount of gas in a container is inversely proportional to the container’s volume (P1V1=P2V2)
25
what is Henry's law
amount of gas dissolved in a liquid is proportional to the partial pressure of gas which which the liquid is in equilibrium with
26
what is the alveolar gas equation
PAO2 = PiO2 - PaCO2/R
27
what is the Law of Laplace and give the relevant equation
describes the relationship between pressure (P), surface tension (T) and radius of an alveolus (r)
P = 2T/r
28
what are the 5 types of antibodies
```
IgG
IgA
IgM
IgE
IgD
```
29
which antibody is produced first at the beginning of an infection
IgM
30
which type of antibody is the most abundant
IgG
31
which type of antibody is made in response to allergies
IgE
32
what is hypersensitivtiy and which antibody is involved in this
the overreaction of the immune system to things it doesn't need to react to (IgE involved in this)
33
what are the 4 types of hypersensitivity reactions
type I = ALLERGIC (IgE mediated, quick onset after exposure)
type II = CYTOTOXIC/ANTIBODY MEDIATED
type III = IMMUNE COMPLEX (IgG and IgM mediated)
type IV = DELAYED / CELL MEDIATED
34
which type of nerve fibres are sensory
afferent neurons
35
which type of nerve fibres are motor
efferent neurons
36
what are efferent neurons subdivided into
somatic (voluntary) and autonomic (involuntary) nervous system
37
what does the somatic NS innervate
skeletal muscle
38
how many somatic neurons are found between the CNS and an effector muscle
one
39
is the somatic NS excitatory, inhibitory or both
ONLY excitatory
40
what neurotransmitter(s) does the somatic NS use
only ACh
41
what does the autonomic NS innervate
cardiac muscle, glands, neurons in the GI tract and other tissues (not skeletal)
42
how many autonomic neurons are found between the CNS and its innervation
2 neurons synapse
43
where would 2 neurons in the autonomic NS synapse
in a cell cluster outside of the CNS called the autonomic ganglion
44
is the autonomic NS excitatory, inhibitory or both
both
45
what neurotransmitter(s) does the preganglionic neuron in the autonomic NS use
ACh
46
what neurotransmitter(s) does the postganglionic neuron in the autonomic NS use
ACh (excitatory)
| Noradrenaline (inhibitory)
47
what can the autonomic NS be divided into
sympathetic and parasympathetic divisions
48
describe the neurotransmitters involved in pre/postganglionic in the sympathetic NS and what receptors they act on
Preganglionic synapse → ACh acts on nicotinic receptors
Postganglionic synapse → noradrenaline acts on adrenergic receptors
49
what are the effects of the sympathetic NS
```
Increase HR
Increases force of contraction of heart
Vasoconstriction
bronchoDILATION
Sphincter contraction
DECREASED GASTRIC SECRETIONS
REDUCED GASTRIC MOTILITY
Male ejaculation
```
50
describe the neurotransmitters involved in pre/postganglionic in the parasympathetic NS and what receptors they act on
Preganglionic synapse:
ACh acts on nicotinic receptors
Effector cell synapse:
ACh acts on muscarinic receptor
51
describe the effects/innervations of the parasympathetic cranial nerves
```
Decrease HR
Decrease force of contraction of the heart
bronchoCONSTRICTION
Sphincter relaxation
INCREASED GASTRIC SECRETIONS
INCREASED GASTRIC MOTILITY
Male erection
```
52
what are upper motor neurons and where do they synapse
they are the descending pathways and neurons of the motor cortex
they synapse on LMN in the brainstem or the spinal cord
53
what are the signs of an UMN lesion
paralysis/weakness of movements on the affected side
Baninski sign is present - big toe is dorsiflexed and other toes fan outwards
Loss of fine-skilled voluntary movements (especially at distal ends of the limbs
Spasticity or hypertonicity of the muscles
54
what are lower motor neurons
alpha motor neurons that connect UMNs to effectors
55
define: single motor unit
the muscle fibres distributed in one muscle
56
what are the signs of a LMN lesion
Flaccid paralysis of muscles supplied
Atrophy of muscles supplied
Loss of reflexes of muscles supplied
Muscle wasting
Muscle contracture
57
which part of the primary motor cortex is supplied by the anterior cerebral artery
medial aspect (legs)
58
which part of the primary motor cortex is supplied by the middle cerebral artery
lateral aspect (all except legs)
59
what are the 7 layers of gas exchange in the lungs
fluid lining epithelium
layer of alveolar epithelium (type 1 pneumocytes)
basement membrane of epithelial cells (type 1 pneumocytes)
interstitial fluid
basement membrane off capillary endothelium
capillary endothelium
red blood cells
FABIBER (feeling are bad instead be emotionally reserved)
60
what is the henderson hasselbach equation
pH = 6.1 + log ([HCO3-]/(0.03[PCO2])
61
what are the 3 proteins produced in the liver
1. plasma proteins (albumin)
2. clotting proteins (except VII (vWF) and IV (calcium))
3. complement proteins
62
what are the 2 main functions of albumin
1. maintain colloid oncotic pressure
| 2. binding and transport of hydrophobic/large molecules
63
describe phase 1 detoxification in the liver
- oxidation/hydrolysis reactions
- often involved in adding -OH or -SH
- use cytochrome P450 enzyme
- using mainly microsomal enzymes
64
describe phase 2 detoxification reactions in the liver
- conjugation
- often involves adding glucuronic acid
- excretion in bile/urine/faeces
- using mainly non-microsomal enzymes
65
what is stored in the liver
- iron is stored in the form of ferritin
- glycogen (100g)
- minerals (Cu)
- fat soluble vitamins (A,D,E,K)
66
where is vit A stored
stored in Ito cells in the the space of Disse
67
what does vit D do
increases Ca and P reabsorption in the GI tract
68
which clotting factors are vit K dependent
10, 9, 7, 2
69
describe the process of fat metabolism
- bile salts emulsify fats in the small intestine and form micelles
- intestinal lipase degrades triglycerides
- triglycerides are incorporated with cholesterol into chylomicrons
- hepatic lipase releases fatty acids and glycerol and allow fatty acid uptake into hepatocytes
- fatty acids are then oxidised or esterified to triglycerides for storage
70
where are LDLs formed and what do they do
- formed in the plasma
| - deliver cholesterol to cells throughout the body
71
where are HDLs formed and what do they do
- formed in the liver
| - remove excess cholesterol from blood and tissues
72
where are VLDLs formed and what do they do
- synthesised in hepatocytes
| - carry triglycerides from glucose in liver to adipocytes
73
describe the urea cycle
Arginine --(-urea)-->ornitihine --(+ ammonia and CO2)--> citrulline --(+ammonia)-->Arginine
Urea is the only product made
74
what is the innervation and and artery supply to the foregut
- coeliac trunk
| - greater splanchnic (T5-T9)
75
what is the innervation and artery supply to the midgut
- superior mesenteric artery
| - lesser splanchnic (T10-T11)
76
what is the innervation and artery supply to the hindgut
- inferior mesenteric artery
| - least splanchnic (T12)
77
what forms the ampulla of Vater and where does this enter the duodenum
- bile duct and pancreatic duct
| - ampulla of vater enters the 2nd part of the duodenum at the major papilla
78
which part(s) of the duodenum is smooth muscle and what does the rest contain
- the first part of the duodenum is smooth
| - the rest contains plicae circularis
79
what are the differences between the jejunum and the ileum
LENGTH - J=2/5, I=3/5
DIAMETER - J=wider
WALL - J=thicker
COLOUR - J=deep red, I=pale pink
PEYER'S PATCHES - J=fewer, I=more
BLOOD SUPPLY - J=longer vasa recta, fewer arcades
MESENTERY - J=transparent (less fat), I= more fat
80
what are peyer's patches
small masses of lymphatic tissue found throughout the ileum
81
what is the porta hepatis
where the neurovascular vessels (EXCEPT VEINS) enter and leave the liver
82
describe the billary tree
left + right hepatic duct = common hepatic duct
common hepatic duct + cystic duct = common bile duct
common bile duct + pancreatic duct = ampulla of vater
83
what are the 4 layers of the GI tract
1. mucosa
2. submucosa
3. muscularis externa
4. serosa
Ms & Ms
84
which embryological layer forms the foregut, midgut and hindgut
endoderm
85
describe the phases of swallowing
Stage 1 - voluntary
- Food compressed against the roof of the mouth and pushed towards the oropharynx by the action of the tongue
- Buccinator and suprahyoid muscles manipulate food
Stage 2 - involuntary:
-Nasopharynx closed off by the soft palate
pharynx shortened/widened by elevation of the hyoid bone
Stage 3 - involuntary
- Sequential contractions of the constrictor muscles followed by the depression of the hyoid bone and pharynx
- Peristalsis
86
name the afferent and efferent nerves involved in the gag reflex
```
afferent = glossopharyngeal
efferent = vagus
```
87
what are the main functions of the saliva
- lubrication for mastication
- maintains oral pH of 6.2-7.4 (bicarbonate/carbonate)
- digestive enzymes = salivary alpha amylase
88
name the salivary glands and what type of saliva it produces
PAROTID
- serous saliva
main source of saliva when activated
SUBMANDIBULAR
- serous and mucous saliva
SUBLINGUAL
- mucous saliva
89
what is the effect of sympathetic and parasympathetic effect on salivary glands
sympathetic - inhibits
| parasympathetic - stimulates
90
describe serous acini
- dark staining nucleus
- small central duct
secrete water and alpha amylase
- found mainly in parotid gland
91
describe mucous acini
- pale staining
- nucleus at the base
- large central duct
- secrete mucous (water and glycoprotein)
92
what connects acini to striated ducts and what is the function
- intercalated ducts
| - NaCl
93
what do parietal cells produce and what do they do
HCl - digestion, activation of pepsinogen, host defense
Intrinsic factor - involved in the absorption of B12 in the terminal ileum
94
what do chief cells produce and what does it do
Pepsinogen - inactive form of pepsin which breaks down proteins
95
what do enterochromaffin (ECL) cells produce and what does it do
```
Enterochromaffin cells (ECL cells)
Histamine - upregulates HCl secretion from parietal cells
```
96
what do G cells produce and what does it do
Gastrin - upregulates HCl secretion
| binds to parietal and ECL cells
97
what do D cells produces and what does it do
Somatostatin - inhibits gastrin secretion
98
ACh
- site of production
- site of action
- action
neurons
ECL cells and parietal cells
stimulates histamine and HCl secretion
99
Gastrin
- site of production
- site of action
- action
G cells
ECL cells and parietal cells
stimulate histamine and HCl secretion
100
histamine
- site of production
- site of action
- action
ECL cells and mast cells
H2 receptors on parietal cells
stimulates HCl secretion and increases response to gastrin/HCl
101
somatostatin
- site of production
- site of action
- action
D cells
parietal cells
inhibits HCl secretion
102
secretin
- site of production
- site of action
- action
S cells (small intestine)
G cells
inhibits gastrin secretion
103
CCK
- site of production
- site of action
- action
I cells (small intestine)
parietal cells and pancreas
inhibits HCl secretion and promotes flow of digestive enzymes from pancreas/ bile salts
104
what is the volume of an empty stomach vs when it is full
```
empty = 50ml
full = 1.5 litres
```
105
what is receptive relaxation WRT the stomach and what is it mediated by
- dilation of the body/fundus just before food arrives
| - mediated by parasympathetic NS (vagus nerve)
106
describe peristalsis in the stomach
- peristaltic waves begin in the body of the stomach which are weak and cause little mixing
- more powerful contractions occurin the gastric antrum
- pyloric sphincter closes as the peristaltic wave reaches it
- little chime will enter the duodenum
- the majority rebounds to the antrum and is forced backwards towards the body to be mixed
107
what are the 4 gastric mucosal defences
1. alkaline mucous on luminal surface
2. tight junctions between epithelial cells
3. rapid replacement of damaged cells by stem cells present at the base of pits
4. feedback loops for regulation of gastric acid secretion
108
which are the fat soluble vitamins and where are they absorbed
- A, D, E, K
| - absorbed in micelles the same way as fat in the ileum
109
which are the water soluble vitamin and where are they absorbed
-B, C
- jejunum
(exception is B12)
110
describe the process of B12 absorption
1. B12 bonds with R-protein in the mouth
2. R-protein protects B12 from the HCl in the stomach
3. protease in the duodenum releases B12 from R-protein
4. intrinsic factor produced by parietal cells in the stomach help B12 to be absorbed
111
describe the digestion of starch
1. begins in the mouth with alpha-amylase (pH 6.7)
2. 95% of digestion is done by pancreatic amylase in the small intestine
3. this produces maltose and a mixture of other chains
4. the products are broken down into monosaccharides by oligosaccharide and disaccharide enzymes of the luminal membranes of the small intestine
112
what are the 3 monosaccharides
glucose
fructose
galactose
113
describe the digestion of proteins
STOMACH
- partially broken down to peptide fragments in the stomach by pepsin
SMALL INTESTINE
- peptide fragments are further broken down by proteolytic pancreatic e enzymes (trypsin and chymotrypsin)
114
what are the proteolytic pancreatic enzymes
trypsin and chymotrypsin
115
describe the process of protein absorption
- most of the products of protein digestion are absorbed in short chains of 2/3 A.As by secondary active transport coupled to the H+ gradient
- free A.As enter the epithelial cells by secondary active transport coupled to Na+ facilitated by an increase in luminal Na+ concentration
- these A.As then leave the cell and enter the interstitial fluid via facilatated diffusion
- diffuse passively into the blood
116
describe the digestion of fat
- major digestive enzyme is lipase which is synthesised in the pancreas
- catalyses the splitting of bonds linking fatty acids to the 1st and 3rd carbon atoms of glycerol producing two free fatty acids and a monoglyceride
117
what are the classifications of BMI
```
BMI > 40 = morbidly obese
30 < BMI < 40 = obese
25 < BMI < 30 = overweight
18.5 < BMI < 25 = normal
BMI < 18.5 = underweight
```
118
what is BMI measure in
weight (Kg) / height^2 (m)
119
how much excess glycogen can be stored and how long does it last
- 15 kg
| - 12 hours
120
how much excess lipid can be stored and how long does it last
- 350 g (200g in liver, 150g in skeletal muscle)
| - 3 months
121
how much excess protein can be stored and how long does it last
- 6kg
- 10 days
(only used in periods prolonged starvation)
122
briefly describe the 2 functions of the pancreas
EXOCRINE
- acini of pancreas produce digestive enzymes that are released via the pancreatic duct
ENDOCRINE
- islets of langerhans produce insulin and glucagon which regulate blood glucose levels
123
what do alpha cells secrete and what is its function
- glucagon
| - raised blood glucose
124
what do beta cells secrete and what is its function
- insulin
| - lowers blood glucose
125
what do delta cells secrete and what is its function
- somatostatin
| - inhibits glucagon and insulin secretion
126
what is the function of the gallbladder
the site where bile is stored and concentrated
127
describe how bile is secreted from the gallbladder
1. CCK triggers the gallbladder to contract and release bile into the cystic duct
2. this emptys into the common bile duct which joins with the pancreatic duct to form the ampulla of vater
3. this enters into the duodenum where bile emulsifys fat
128
define hormone
signalling molecule produced in a gland which travels to a target organ to regulate physiology and behaviour
129
define endocrine
secrete hoemones into the blood to regulate distant target organs
130
define exocrine
secrete substances via a duct
131
define paracrine
cell to cell communication to induce changes in nearby cells
132
describe the three types of hormones
AMINE
- derived from A.As (catecholamines, thyroxine)
PEPTIDE
- made from peptide
- stored in secretory granules
- rapid release and short action
STEROID
- made from lipids
- travel in the plasma bound to proteins
- slow release and long action ie cortisol
133
what hormones does the anterior pituitary gland produce
1. TSH (thyroid stimulating hormone)
2. FSH
3. LH
4. ACTH (adrenocorticotropic hormone)
5. Growth hormone
6. prolactin
134
where does FSH act in males and females and what does it do
FEMALES
- stimulates the growth of ovarian follicles in the ovary before ovulation
MALES
- acts on SERTOLI cells to stimulate spermatogenesis
135
where does LH act in males and females and what does it do
WOMEN
- in weeks 1 and 2 of the menstrual cycle it stimulates ovarian follicles to release estrogen
- around day 14 a surge in LH causes ovulation
MALES
- acts on LEYDIG cells to produce testosterone (which acts locally to support sperm cell production)
136
what is another name for the anterior pituitary and where is it derived from embryologically
- anterior pituitary = adenohypothesis
| - derived from the GI tract
137
what is another name for the posterior pituitary gland and where is it derived from
posterior pituitary = neurohypothesis
| - neural tissue
138
name the major hormones secreted by the posterior pituitary gland and which nucleus they are released from
PARAVENTRICULAR NUCLEUS
- located in the hypothalamus
- releases oxytocin
SUPRAOPTIC NUCLEUS
- located in the hypothalamus
- releases ADH (vasopressin)
139
what are the layers of the adrenal cortex and what do they produce
zona glomerulosa - mineralcorticoids (aldosterone)
zona fasiculata - glucocortiocoids (cortisol)
zonal reticularis - androgens (DHEA)
140
what is produced in the adrenal medulla
catecholamines
| - adrenaline, noradrenaline and some dopamine
141
what activates the zona glomerulosa and what does it act on
activated by:
1. Angiotensin II (RAAS)
2. hperkalaemia
acts on:
1. DCT
2. CD
(increases water and Na+ reabsorption, increases K+ secretion
142
what activates the zona fasiculata and what does it do
- secretes glucocorticoids in response to ACTH secretion from the anterior pituitary gland
- negative feeback on the anterior pituitary
- results in giht or flight response
143
describe the action of cortisol
1. increases metabolism by:
- protein breakdown
- gluconeogenesis
- insulin resistance
2. circulation:
- increases vasoconstriction
3. decreases inflammation and specific immune responses
4. decrease of non-essential functions (ie reproduction/growth)
144
how many lobes are there of the thyroid gland and what connects them
- 2 lobes
| - connected by the isthmus
145
describe the vasculature of the thyroid gland
ARTERIAL SUPPLY
- superior and inferior thyroid artery
external carotid artery --> superior thyroid artery
subclavian --> thyrocervical trunk --> inferior thyroid artery
VENOUS DRAINAGE
- superior, middle and inferior thyroid veins
146
describe the synthesis of T3/4
- Thyroglobulin produced in ER of follicle cell travels to the lumen
- Iodide travels from plasma, through the cell, into the lumen.
- Peroxidase converts Iodide to Iodine
- Iodine replaces OH groups on Tyrosine rings making MIT + DIT
- MIT + DIT combine via ester bonds to make T3 + T4
- T3/T4/MIT/DIT travel from lumen into follicle cells, packaged in endosomes
- Lysosomes cleave T3/T4 as required from endosomes
- T3/T4 diffuse freely through the apical membrane
147
what is the action of T3/4
- increased metabolic rate
- growth and development
- increased catecholamine effect (symp NS)
148
how is T3/4 transported in the blood
bound to thyroid binding protein
149
out of T3 and T4 which is the more active form and which is more prevelant
T3 - more active form
| T4 - more prevalent
150
what are the 3 hormones that regulate Ca2+ uptake and what effect do they have
1. vit D - increases Ca2+
2. PTH - increases Ca2+
3. calcitonin - decreases Ca2+
151
what cells produce and release PTH from PTH glands
chief cells
152
what are the actions of parathyroid hormone
1. osteoclast proliferation/differentiation
2. reabsorption of Ca2+ in the DCT
3. increases production of activated vit D (via increase in action of 1 alpha hydroxylase)
153
describe the synthesis of vit D
7-dehydrocholesterol in skin is converted to cholecalciferol (vitD3) by UV B
this is converted to 25(OH)vit D in the liver
this is converted to 1,25(OH)2 vit D in the kidneys via 1 ALPHA HYDROXYLASE
(activity of this enzyme is increased by PTH)
154
where is calcitonin released and what are its actions
released from the thyroid gland when Ca2+ levels are too high
activity:
- promotes bone deposition
- inhibits Ca2+ resorption in the kidneys
opposite effect of PTH
155
where are the receptors for peptide and steroid hormones located
peptide - cell membrane
| steroid - intracellular
156
how do you calculate the anion gap
anion gap = (Na+ + K+) - (Cl- + HCO3-)
157
what are the 4 main energy sources for catabolism
carbohydrates
lipids
proteins
alcohol
158
does hyperthyroidism or hypothyroidism INCREASE BMR
hyperthyroidism
159
approx how much of excess energy intake is stored as protein
6kg
160
what are the bonds between phosphate groups on ATP called and are they strong or weak
- phosphoanhydride bonds
| - relatively weak
161
what is the overall equation for aerobic glycolysis
glucose --> 2 pyruvate + 2 ATP + 2 NADH
162
what is the overall equation for anaerobic glycolysis
glucose --> 2 lactate + 2 ATP
163
what inhibits krebs cycle
Succinyl CoA
ATP
NADH
164
what activates krebs cycle
ADP
165
what is the total number of ATP produced in aerobic respiration
34
166
what enzyme converts acyl carnitine to acyl CoA and where does this take place
carnitine acyltransferase 2
mitochondria
167
which ion has little effect on the anion gap
K+
168
how is total body water distributed in a healthy 70kg man
intracellular 28L
extracellular 14L
--> intravascular 3L
--> interstitial 11L
169
what is the main cation in extracellular fluid
Na+
170
what is the main cation in intracellular fluid
K+
171
define osmolarity
conc of solutes in plasma per:
KILOGRAM of SOLVENT
LITRE of SOLUTION
172
what does the right coronary artery supply
right ventricle
right atrium
SA and AV nodes
173
define fasciculi
nerve axons that run up and down the spinal cord in bundles
174
Dorsal/medial lemniscal column
- function
- decussation
- lateral vs medial
FUNCTION
- proprioception, vibration and discriminative touch
DECUSSATION
- medulla
LATERAL
- fasciculus cuneatus - carries info from the upper body to the cuneate tubercle in the medulla
MEDIAL
- fasciculus gracilis -carries info from the lowerr body to the gracile tubercle in the medulla
175
lateral and medial spinothalamic tract
- function of lateral and medial
- decussation
- where the tracts join
FUNCTION
LATERAL - pain and temp
MEDIAL - crude touch
DECUSSATION
- ascends on the same side for 1 to 2 levels then descussates before ascending to the thalamus
JOIN
- the tracts join at the medulla and carries on to the thalamus
176
corticospinal tract
- function
- decussation
- lateral vs medial
FUNCTION
- transmits control of voluntary muscles (motor)
DECUSSATION
LATERAL (75%) - pyramidal medulla decussation (limbs)
MEDIAL (25%) - decussates as it leaves the spinal cord via the anterior white commissure (axial muscles)
177
what sensory nerve endings may sense fine touch
1. meissner's corpuscle
2. pacinian corpuscle
3. ruffini endings
4. mekels endings
178
how many nerves are involved in the DMLC tract
3 neurons:
1. in the dorsal root ganglion
2. in the cuneate and gracile nuclei
3. in the ventral posterolateral nucleus of the thalamus
179
describe the effect of brown-sequard syndrome
1. ipsilateral weakness (due to DMLC)
2. ipsilateral loss of dorsal column proprioception
3. CONTRALATERAL loss of spinothalamic pain and temperature
overall:
ipsilateral loss of: proprioception, motor and fine touch
contraleteral oss od: pain, temp and crude touch
180
what are the parasympathetic effects of CN III
1. pupil constriction
| 2. accommodation (focusing near to far objects)
181
what muscle controls movement of the eyelid
levator palpebrae superioris muscle
182
what would damage to the trochlear nerve cause
double vision as the patient looks down
183
where do the afferent branches of the trigeminal nerve meet
meckel's cave
184
what are the parasympathetic functions of the facial nerve
- submandibular and sublingual salivary glands
- nasal, palatine and pharyngeal mucous glands
- lacrimal glands
185
where does the facial nerve begin to branch and what are the branches
- within the parotid gland
- temporal branch
- zygomatic branch
- buccal branch
- marginal mandibular branch
- cervical branch
186
what are the parasympathetic, motor and sensory functions of glossopharyngeal nerve
```
PARASYMPATHETIC
- parotid gland
MOTOR
-elevates the pharynx
- stylopharyngeal
SENSORY
- external ear
posterior 1/3 of tongue
- pharynx (touch/pain/temp)
- Eustachian tube (touch/pain/temp)
- carotid sinus & body (baro/chemoreceptor)
```
187
describe the innervation of the tongue
POSTERIOR 1/3
sensory and taste - glossopharyngeal
ANTERIOR 2/3
sensory - lingual branch of V3
taste - chorda tympani branch of facial
MOTOR
hypoglossal except palatoglossus (pharyngeal branch of vagus)
188
what passes through the cavernous sinus
CN III, IV, V1, V2, VI
| internal carotid artery
189
where is wernicke's area located
temporal lobe
190
where is the most common location of a berry anuersym and what does it cause
anterior cerebral artery and anterior communicating artery junction
subarachnoid heaemorrage
191
how is fibrin broken down
plasminogen --> plasmin which breaks down fibrin
192
what is the function of titin
maintains the alignment of thick filaments in the middle of each sarcomere
193
describe cardiac action potentials
0 - rapid depolarisation (Na+ influx)
1 - partial repolarisation (Na+ stops, K+ efflux)
2. plateau (slow inflow of Ca2+)
3. repolarisation (Ca2+ stops, K+ efflux)
4. rest,
194
what is the function of intercalated discs
- they are junctions that contain desmosomes and adherent junctions that binds cells together
- contain gap junctions that allow cells to become electrically coupled
195
differentiate between action potentials in cardiac myocytes vs skeletal muscles
CARDIAC MYOCYTES
- long plateau due to the influx of calcium
- extended refractory period allows the cell t fully contract before another electrical event can occur
- AUTORHYTMICITY - cardiac muscles can initiate its own electrical impulse that trigger the mechanical contraction
196
which component of the heart conduction system would have the slowest firing rate
purkinje fibres
197
what would the heart rate be if the SA node was blocked
40-60 bmp
198
describe the order of valves opening/closing in the cardiac cycle in the left side of the heart
mitral valve closes
aortic valve opens
aortic valve closes
mitral valve opens
COCO MAAM
199
list 5 constituents of plasma
salts, nutrients, antibodies, hormones and other bio-active constituents
200
n some cases however immature red cells still containing some visible ribosome remnants may be released into the blood stream. What are these cells called?
Reticulocytes
201
what layer do veins not have
external elastic lamina
202
what 3 layers do all arteries and veins contain
external to innermost
- tunica adventitia
- tunica media
- tunica intima
203
what are the 4 ways in which the structure of arteries and veins differs
1. outline - A=circular, V=irregular
2. musclular wall - A=thick, V=thin
3. diameter - A=smaller, V=larger
4. Valves - A=none, V=present
204
what are the 4 starling forces that determine net filtration pressure (NFP)
1. hydrostatic pressure in the capillary
2. hydrostatic pressure in the interstitium
3. oncotic pressure in the capillaries
4. oncotic pressure in the interstitum
205
how does the kidney detect changes in blood pressure
strech receptors in the vascular walls or by macula densa cells (NaCl)
206
describe the changes to foetal circulation that occur at birth
First breaths of life -> lungs expand -> the alveoli in the lungs are cleared of fluid.
An increase in the baby's BP and a significant reduction in the pulmonary pressures reduces the need for the ductus arteriosus to shunt blood -> closure of the shunt.
These changes increase the pressure in the left atrium of the heart -> decrease the pressure in the right atrium -> foramen ovale closes -> newborn circulation.
207
name the local constrictors of blood vessels
endothilin -1
| local BP
208
name the local dilators of blood vessels
```
NO
bradykinin
prostacyclin
H+, K+, H20
hypoxia
adenosine
tissue breakdown products
```
209
name the hormonal constrictors of blood vessels
adrenaline
vasopressin
angiotensin II
210
name the hormonal dilators of blood vessels
adrenal
| atrial natriuetic peptide (ANP)
211
name the neural vasoconstrictor/dilator on blood vessels
noradrenaline
212
what is the main determinant of population health
the extent of income division
213
what is the Gini coefficient
statistical representation of national income distribution
lower Gini coefficient = greater equality
214
2 responses to health inequality (reports)
```
black report (1980)
acheson report (1988)
```
215
what is proportionate universalism
Proportionate universalism is the resourcing and delivering of universal services at a scale and intensity proportionate to the degree of need.
Services are therefore universally available, not only for the most disadvantaged, and are able to respond to the level of presenting need.
216
give 3 theories of causation of health inequality
1. psychosocial - stress, impact on blood pressure, cortisol levels, inflammatory response
2. neo-material - heirarchial societies invest less in public goods
3. life course - combination of above, critcal periods and accumulation
217
what are the 4 domains of public health
1. health protection
2. improving services
3. health improvements
4. addressing wider determinants of health
WISP
218
what are the 3 ethical levels
1. meta-ethics
2. ethical theory
3. applied theory
219
explain a deductive ethical argument
one general ethical theory applies to all medical ethics
220
explain a inductive ethical argument
use settled medical cases to generate ethical theory
221
explain the 4 parts of the biomedical model of health
1. mind and body are separate
2. body, like a machine, can be repaired
3. privilages use of technological interventions
4. neglets social and psychological dimensions of disease
222
give the 5 structural determinants of illness
1. social class
2. poverty
3. unemployment
4. discrimination
5. gender and health
223
when is a breach of confidentiality allowed
1. required by law
2. public interest
3. patient consents
224
what is the criteria for disclosure of patient information
1. anonymous if practical
2. patients consent
3. minimum amount of info possible
4. meets law
225
what are the 3 main notifiable diseases for breach of consent
cholera
yellow fever
plague
226
explain consequentialism
an act is evaluated on its consequences
227
what is the difference between rule consequentialism and act consequentialism
rule - belief that rules are in place for the good of society
act - belief that you should evaluate actions based on outcome not on rules
228
explain the doctrine of double effect and give an example
This doctrine says that if doing something morally good has a morally bad side-effect it's ethically OK to do it providing the bad side-effect wasn't intended. This is true even if you foresaw that the bad effect would probably happen.
ie euthanasia, giving drugs to ease pain even if it may shorten life
229
what is deontology
evaluating inherent worthiness of action, not outcome
duty based ethics
230
explain a virtue
the trait of a character manifested in a habitual action
231
give the 4 ethical principles
1. autonomy
2. beneficence
3. non-maleficence
4. justice
232
what is a health behaviour
a behaviour aimed to prevent disease
233
what is an illness behaviour
behaviour aimed to seek remedy
234
what is a sick role behaviour
a behaviour aimed at getting well
235
give three examples of preventative medicine / disease prevention
screening
immunisation
child health protection
236
explain the health belief model (how people change their behaviour)
1. believe they are susceptible to a disease
2. believe it has serious consequences
3. believe taking action reduces risk
4. benefits outweigh costs
237
give the 6 stages of the transtheoretical model (quitting smoking)
1. pre-contemplation
2. contemplation
3. preparation
4. action
5. maintenance
6. relapse
238
define morality
the concern with distinction between good and evil
239
what is the ABC list for HIV safety
abstain
be faithful
condom use
240
what is the WHO definition of obesity
Abnormal or excessive fat accumulation resulting from chronic imbalance between energy intake and energy expenditure that presents a risk to health. It is a state of positive energy balance.
241
what are the 7 key domains of energy balance
1. food environment
2. food consumption
3. individual activity
4. activity of the environment
5. societial influences
6. individual psychology
7. individual biology
242
what is the sacral outflow of the parasympathetic NS
S2-4
243
which oif the pre/post ganglionic fibres in the sympathetic NS is short and which is long
short preganglionic
| long postganglionic
244
describe the order of flow of CSF
lateral ventricles
foramen of monro
3rd ventricle
cerenbral aqueduct
4th ventricle
laterally - foramen of Luschka (superior)
medially - foramen of magendie (inferior)
245
what makes up the striatum
caudate nucleus
| putamen
246
what is the function of the limbic system
emotion, memory, drive related behaviour (thirst/hunger)
247
what makes up the limbic system
```
Cingulate gyrus
corpus callosum
mammillary bodies
fornix
hippocampus
amygdala
hypothalamus
```
(cant control my feelings, HAH)
248
what it found at either end of the fornix
mammillary bodies
| amygdala
249
what are the 3 areas of the midbrain
crus cerebri
tegmentum
tectum
250
what does the tegmentum contain
substantia nigra
red nuclei
cerebral aqueduct
oculomotor and trochlear nuclei
251
what does the tectum contain
inferior and superior colliculi
252
where does the spinal cord start and finish
between foramen magnum and cauda equna
| C1-L1/2
253
how many pairs of spinal nerves are there
31
254
what substances are found in the substansia nigra
melanin (dark pigment)
| dopamine (causes parkinsons if deficient)
255
what is the effect of decreased dopamine in the substansia nigra
parkinsons
256
where are ureteric stones likely to stop
renal pelvis
where it crosses the pelvic brim
pelviuretitic junction
uretero-vesical junction
257
describe the testicular vein drainage and its clincial relevance
- pampiniform plexus
- right drains directly into IVC
- left drains into renal vein
clinical relevance - can cause swelling of the left testes
258
name the branches of the abdominal aorta
- coeliac trunk ,SMA, IMA
- renal, gonadal, middle suprarenal
- median sacral and 2x femoral iliac
- inferior phrenic and 4 lumbar
259
what cells are responsible for the production of catecholamines
chromaffin cells
260
name the arteries supplying the kidneys from large to small
```
aorta
renal
segmental
interlobar
arcuate
interlobular
afferent
glomerular
efferent
```
all really sexy interns are imprisoned after general elections
261
what are the contents of the spermatic cord
- pampiniform plexus
- ductus deferens
- cremasteric artery
- testicular artery
- artery of ductus deferens
- genital branch of the genitofemoral nerve
- sympathetic nerve fibres
- lymphatic vessels
pills dont contribute to a good sex life
262
what are the layers of the glomelular filtration
fenestrated capillary endothelium
basement membrane
foot processes of podocytes
263
describe the descending limb of LOH
thin descending
permeable to water
not perrmeable to salt
264
describe the ascending limb of LOH
thick ascending
permeable to salt
impermeable to water
265
what are the 5 ligaments of the liver
flaciform
teres
2 triangular
coronary
266
what is the ligamentum teres a remenant of
the umbilical vein
267
describe the 3 types of cells in the liver
hepatocytes - functional cells (store glycogen and triglycerides)
stellate cells - supporting cells
kupffer cells - specialised macrophages (breakdown of RBCs)
268
what is the cause of jaundice
excess of bilirubin in the blood
269
what is the equation to calculate transpulmonary pressure
alveolar pressure - intrapleural pressure
270
what is the difference between retrospective cohort studies and case control studies
RETROSPECTIVE COHORT
- know outcome
- compare the risk of ALREADY KNOWN exposure factors on disease outcome
CASE CONTROL
- know outcome
- tries to determine possible exposure factors
271
what is the difference between retrospective and prospective cohort studies
RETROSPECTIVE
- know outcome
- compare the risk of ALREADY KNOWN exposure factors on the disease outcome
PROSPECTIVE
- dont know outcome
- compare the effects of high and low risk factors on if a disease is developed
272
what is the gold standard of evidence evidence based medicine
randomized control trial
273
what is prevelance
how much a disease exists in an entire population in a point in time
274
what is incidence
number of NEW CASES in a population in a point in time
275
define evidence
a pattern of results that make you think something
276
where are peripheral chemoreceptors found
aortic and carotid bodies
277
where are central chemoreceptors found
medulla
278
what causes the oxygen dissociation curve to shift left
- increase in pH
- decrease in CO2
- decrease in Temp
- decrease in 2,3 - DPG (reduces oxygen affinity of Hb)
279
what causes the oxygen dissociation curve to shift right
- decrease in pH
- increase in CO2
- increase in temp
- increase in 2,3 - DPG (reduces oxygen affinity of Hb)
280
what is the role of 2,3 - DPG
it decreases the oxygen affinity of Hb
281
is venous or arteriole blood more acidic and why?
venous blood is slightly more acidic because there is more CO2
282
what are the 4 types of hypoxia
- hypoxic hypoxia
- anemic hypoxia
- circulatory hypoxia
- histoxic hypoxia
283
what is the main drive to breathe
hypercapnia (too much CO2 in blood)
284
what is the effect of type 1 resp failure
- hypoxia (pO2 is low)
| - no hypercapnia (pCO2 normal or low)
285
what is the effect of type 2 resp failure
- hypoxia (pO2 is low)
| - hypercapnia (pCO2 is high)
286
what is the cause of type 2 respiratory failure
hypoventilation
287
what is the cause of type 1 respiratory failure
pulmonary embolism
288
what is peak expiratory flow (PEF)
a person's maximum speed of expiration
289
in what order does air move through the resp system
```
trachea
main bronchus
lobar bronchi
segmental bronchi
terminal bronchioles
respiratory bronchioles
alveolar ducts
```
290
how many segmental branches are present in each lung
LEFT - 8
| RIGHT - 10
291
what is dead space and how much is there in the lungs
the volume of air not contributing to ventilation
| - 175mls
292
which ECG leads are anterior
V3
| V4
293
which ECG leads are inferior
II
III
AVF
294
which ECG leads are septal
V1
| V2
295
which ECG leads are lateral
I
AVL
V5
V6
296
what is a confounder
something that influences both the independent and dependent variable
CAUSE OF DISEASE ie smoking
297
where does significant (95%) of the data lie on a normal distribution curve
95% of data lies within +/- 2 standard deviations
298
what is a p value
probability of an event occuring given that a null hypothesis is true
299
what is the difference netween primary, secondary and tertiary prevention of disease
PRIMARY
prevents disease occuring (lifestyle changes, fluoridation of water, childhood vaccinations)
SECONDARY
detects disease earlier (screening)
intervention that prevents recurrence of a disease
TERTIARY
minimize complications after diagnosis of disease
300
what is the prevention paradox
interventions can achieve large overall health gains for whole populations but might offer only small advantages to each individual
301
what are Wilson and Junger's screening rules
CONDITION
- important health problem
- well understood
- detectable at early stage
TREATMENT
- accepted treatment
- facilities for diagnosis/treatment available
- adequate health service provision available
TEST
- suitable test
- test should be acceptable to population
- should be repeated at regular intervals
RISKS/BENEFITS
- agreed policy
- costs should be balanced
- psychological/physiolgical risks should be less than the benefit
302
define sensitivity
proportion of people who are correctly identified with a disease (true positive)
303
define specificity
proportion of people correctly identified without the disease
304
how to calc positive predictive value
proportion of CORRECTLY identified with disease / proportion of people identified with the disease
305
how to calc neg predictive value
proportion of people CORRECTLY identified without the disease / prop of people identified without the disease
306
what is screening length-time bias
screenings happen at regular intervals, may miss those with short term disease/ only pick up those with long, slow growing tumours
307
what is screening lead-time bias
if a disease affects 2 people (A and B) at the same and they die at the same time but A had a screening earlier, it appears A survived longer with the disease when they didn't
308
what is the difference between risk and odds
RISK
new cases in a period of time / total at risk at the start of the time period
ODDS
cases vs non-cases
309
how do you calculate the number needed to treat for one person to benefit
1/absolute risk reduction
310
how do you calculate the absolute risk reduction
absolute risk of control group - absolute risk of effected group
311
define utilitarianism
concerned with the most benefit for the most people
"actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness."
312
describe the process of fertilisation
- in the fallopian tubes sperm penetrates the ZONA PELLUCIDA
- acrosome reaction occurs
- this causes the zona pellucida to harden to prevent other sperm entering
- meiosis 2 of secondary OOCYTE occurs to produce OVUM
- fusion of nuclei leads to ZYGOTE
313
describe blastocyte formation from a zygote to implantation
- zygote
- divisions occur - cleavage + compaction
- morula = 16 cells
- cells fuse to form blastocyst with inner cell mass and trophoblast
- 'hatching' occurs
- implantation
314
what is the difference between morula and blastocyst
MORULA
- 3-4 days after fertilisation
- mass of 16 totipotent cells
BLASTOCYST
- 4-5 days after fertilisation
- has a cavity inside the zona pellucida along with an inner cell mass
315
what forms from the inner cell mass
bilaminar disc
316
what makes up the bilaminar disc
epiblast and hypoblast
317
when and where does the mesoderm form from
forms from the ectoderm during gastrulation
318
what do the 3 germ layers form from
epiblast --> ectoderm
Hypoblast --> endoderm
Ectoderm --> mesoderm
319
what does the ectoderm develop into
- epidermis of skin/hair/nails
- mammary, sweat and sebaceous glands
- CNS nd PNS
- posterior pituitary gland
- enamel of teeth
- lens of the eye and parts of the inner ear
- sensory epithelium of nose/eye/ear
320
what does the endoderm develop into
epithelial lining of the gastrointestinal tract, resp tract and urinarry bladder
- parenchyma of the thyroid gland, parathyroid glas, liver and pancreas
- epithelia lining of the tympanic cavity and auditory tube
- plays a part in the development of the notochord
321
what does the mesoderm develop into
- all of the musculoskeletal system
- deep layers of the skin
- abdominal and chest wall lining
- the WALLS of the bowel
- the urogenital system
322
describe the embryology of the heart
MESODERM
- 2 tubes fuse to form 1 primitive heart tube
- longitudinal and lateral folding
- tube undergoes SEPTATION (seperating left/right sides of the heart)
- atrial septation - primary and secondary septum (foramen ovale --> fossa ovalis) and ventricular septation
- 6 aortic arches
- ductus arteriosus --> ligamentum arteriosus
323
describe the embryology of the resp system
ENDODERM
- trachea buds off oesophagus (pharyngeal foregut)
- epithelial layer forms from endoderm
- lung buds rapidly divide (branching morphiogenesis)
- asymmetry (2 lobes vs 3 lobes)
- cartilage, smooth muscle, pleura derived from MESODERM
- cuboidal epithelium converted to simple squamous in the alveoli
324
describe the embryology of the GI tract
ENDODERM
foregut = lower oesophagus --> ampulla of vater
midgut = ampulla of vater --> 2/3 along transverse colon
hindgut = 2/3 along transverse colon dentate line
- midgut leaves through umbilicus, loop rtates out of abdomen then reenters
- smooth muscle, connective tissue and visceral peritoneum dervived from MESODERM
325
what is the telecephalon
cerebral cortex
326
what is the diencephalon
thalamus and hypothalamus
327
what is the metencephalon
pons and cerebellum
328
what is the myelencephalon
medulla oblongata
329
what is the prosencephalon
forebrain
330
what is the mesencephalon
midbrain
331
what is the rhombencephalon
hindbrain
332
what marks the start of gastrulation and which day does this occur
formation of the primitive streak on day 15
