Last minute finals revision Flashcards
1
Q
Where does the conversion of G-6-P to Glc occur in gluconeogenesis?
A
In the lumen of the ER usin G-6-phosphatase
2
Q
What does the pentose phosphate pathway produce?
A
NADPH
3C-7C sugars
3
Q
What enzyme is used in step 6 of glycolysis?
A
Glyceraldehyde-3-Phosphate Dehydrogenase
4
Q
What does the parasympathetic system do in the eye?
A
Muscarinic Receptors
- > ciliary muscle contracts
- > Eye focuses close up
5
Q
What do B2 receptors do in the eyE?
A
B-2 receptors
- > Cililary muscle relaxes
- > lens focusses far away
6
Q
What do alpha-2 receptors do in the eye?
A
Alpha-2 receptor
- > radial muscle contracts
- > Pupil is dilated
7
Q
What is the funciton of B1 receptors in the hearT?
A
B1 receptor on pacemaker cells
-> Increases heart rate
B1 receptors on myocytes
-> increases contraction strength
8
Q
What do B2 receptors do in the lungs?
A
B2 receptors
- > relax smooth muslce
- > aiways dilate
9
Q
How can we use B1 receptors to slow the heart rate?
A
A beta-1 blocker (antagonist) such as atenolol would slow heart rate
10
Q
How do we use B2 receptors to relieve ashtma ?
A
Beta2 agonist like salbutamol will dilate the airways
11
Q
How does the sympathetic system affect the pancreas?
A
alpha receptors inhibit secreiton of pancreatic enzymes
12
Q
Hwo does the sympathetic system affect the Gut?
A
Both alpha & BEta receptors decrease gut motility
13
Q
How does the sympathetic system affect the bladdeR?
A
B2 receptors relax smooth muscle around the bladder to reduce the need to urinate
Alpha1 receptors contract the sphincter muscle also preventin urination.
14
Q
How does the sympathetic system affect energy stored?
A
Beta 2 receptors stimulate glycogenolysis for Glc
Beta 1 recetpros stimulate lipolysis
Alpha 2 receptors inhibit lipolysis
15
Q
How does the ANS affect your salivary glands?
A
Parasympathetic
- > Muscairnic receptors
- > thin watery secretion
Sympathetic
- > Beta receptors
- > Thick enzyme rich secretion
16
Q
What do each sympathetic receptor generally do?
A
Alpha 1 = gluconeogenesis/vasoconstriction/sphincter constriction
Alpha 2 = Constricts muscle/inhibits energy
Beta 1 = Excitatory/ produces energy
Beta 2 = Smooth muscle relaxant/stimulate glycogenolysis
17
Q
What do alpha 1 receptors do?
A
Constrict sphincter of urethra
Gluconeogensis/glycogenolysis
Vasoconstriction
18
Q
What do alpha 2 receptors do?
A
Inhibits Lipolysis
19
Q
What do beta 1 receptors do?
A
Increase heart rate/contraction strength
Increases lipolysis
20
Q
What do beta 2 receptors do?
A
Relax smooth muscle
Stimulates glycogenolysis
21
Q
Whats the use of blocking isocitrate dehydrogenase?
A
Blocking isocitrate dehydrogenase causes citrate build up
Citrate is then shuttled into the cytoplasm and inhibits phosphofructokinase
This stops excess glycolysis
22
Q
Why block alpha-ketoglutarate dehydrogenase?
A
α-ketoglutarate builds up
Its then used instead to produce amino acids
23
Q
What is citrte used to produce?
A
Fatty Acids
Sterols
24
Q
What is Oxaloacetate used for?
A
CAC
GLuconeogenesis
Making amino acids & pyrimidines
25
What is an anaplerotic reaction?
The act of replacing intermediates that have been removed for biosynthesis. (which is cataplerotic)
I.e. When oxaloacetate is removed from CAC for making amino acids, pyruvate carboxylase kicks in & replaces it direct from pyruvate
26
What are the steps of FA synthesis?
Condensation
Reduction
Dehydration
Reduction
27
What are the steps of B-0xidation?
Oxidation
Hydration
Oxidation
Thiolysis
28
Where does the NADPH for FA syntehsis come from?
Some from Pentose phosphate pathway
| Some from Citrate shuttle
29
What is the glucose uniporter called?
GLUT2
30
How does glycogen form?
1) Glycogenin binds UDP glucose into 8 unit primers
2) glycogen synthase extends the Glc chains
3) glycogen branching enzyme breaks the chain & makes branches
31
How is glycogen broken down?
1) glycogen phosphorylase removes single monomers as G-1-P
2) De-branching enzyme acts as a transferase moving 3 Glc from branch to chain
3) de-branching enzyme acts as a glucosidase breaking the alpha1-6 bond in branch.
32
What is hurlers syndrome?
Mucopolysaccharidoses.
| I.e. a deficiency in the enzymes needed for GAG breakdown
33
What is Von Gierkes disease?
Liver G-6-Pase deficiency
34
What are the symptoms of vongierkes diases?
- High liver gylcogen
- Hypoglycaemia
- lacticacidaemia
35
How do we treat von gierkes?
Regular carb feeding
36
What is mcardles disease?
Skeletal muscle glycogen phosphorylase deficiency
37
Symptims & treatment for mcardles disease?
- High muscle glycogen
- Weakness/cramp & no glc increase after exercise
Avoid streneous activity & use second wind
38
What is poduced when Pyruvate is converted to Acetyl-CoA?
NADH & CO2
| Pyruvate dehydrogenase
39
Which muscle filament is think & which is thin?
Myosin is thick
| Actin is thin
40
What coenzyme accepts electrons in complex 1&2 of the electron transport chain?
Coenzyme 10 or Ubiquinone
41
What carries electrons from complex 1&2 to complex 3?
Ubiquinol
42
What binds nucleotides together?
Phosphodiester bonds
43
What do pacemaker potentials do?
Trigger spontaneoulsy to provide breathing & cardiac ryhtyms
44
What directly generates the resting membrane potential?
The membranes permeability to K+ ions
45
What does ingesting alcohol use up (especially at teh liver)?
NAD+
46
Does the eukaryotic plasma membrane contain ribosomes or cholesterol?
It contains cholesterol but no ribosomes
47
What does Tetrodoxin do?
Blocks soidum channels preventing an AP at the NMJ
48
What does Joro spider toxin do?
Blocks calcium channels stopping transmitter relase at the NMJ
49
What does botulinum toxin do?
Disrupts transmitter release
50
What does curare do?
Blocks Ach receptors preventing an endplate potential
51
What does hemicholium do?
Blocks Choline reuptake preventing Ach production at the NMJ
52
What does Neostigmine do?
Its an acetylcholinesterase inhibitor which prevents breakdown of Ach and thus incerases transmission at the NMJ
53
What is a sarcomere & a Z band?
Sarcomere is the reapeating unit of striated muscle
| A Z band is an area of dense proteins connecting the sarcomeres
54
What are the steps of the cross bridge cycle in skeletal msucle?
- Ca2+ binds to troponin
- Troponin moves tropomysosin exposing Actin binding site
- Cross bridge binds
- ADP +Pi released & cross bridge contracts
- ATP binds to myosin & cross bridge detaches
- ATP hydrolysed ready for next contraction
55
What receptors are involved in contraction at the muscle?
+ DHP receptors in the T tubules detect depolarisation
| They activate ryanodine recptors which activate Ca2+ channels in the SR
56
What is the optimal length of a muscle?
The length that gives the grearest iosmetric tension
57
What is the MM equation?
Vo = Vmax[S] / Km + [S]
58
What is the lineweaver-burke equation?
1 / Vo = (Km / Vmax) (1 / [S]) + (1 / Vmax)
59
Whats a coenzyme?
Complex organic molecule usualy derived from vitamins. Such as NAD+/FAD+/Ubiquinone
60
Whats a prosthetic group?
Cofactor bound or tightly associated to an enzyme
61
How can we see the direction of mechanical forces on bone?
In the direction of the bony trabeculae
62
What bones grow by intramembranous ossification?
Flat Bones
Mandibles
Maxilla
Clavicle
63
Whats the pocess of intramembranous ossification?
Mesenchymal cells develop into osteoprogenitor cells
Osteoprogenitor cells mature to osteoblasts
Osteoblasts lay down bone
64
what hapens to residual mesenchymal stemm cells in intramembranous ossification?
They become blood vessels & marow
65
What makes up the Bone ECM?
45% hydroxyapatite crystals for strength under compression
35% ctype 1 collagen for tension strength
20% water
66
What connects lancunae?
Caniculi
67
What are osteoclasts dervied from?
monocytes.macrophages
68
What is pagets disease?
Where both bone formation & resorption increases
| results in fragile misshapen bone
69
How does menopause affect bone mass?
Oestrogen has an inhibitory affect on bone reabsoroption
| So after menpause the bone mass decerases as oestrogen is no longer produced
70
How much blood is in a new born babay?
350ml
71
What do alpha & beta globulins do?
Transport vitamins
72
What is the result of colloid oncotic pressure?
The volume of the plasma/ISF changes to generate equal concs of plasma proteins.
73
What is fluid movement between ISF & plasma dependant on?
Capillary & interstitial hydrostatic pressures (CHP & IHP))
And intersitial/plasma protein concs
74
What does hypoproteinemia cause?
Oedema due to a lack of oncotic pressure
75
What are myeloid cells?
All blood cells bar lymphocytes
76
What are the stem cells that produce myeloid cells?
Pluripotent hematopoietic stem cells
- > Committed progenitor cells
- > myeloid cell
77
What is the steps in erythrocytes productiosn?
Pluripotent stem cell
- > uncommitted progenitor cell
- > committed progenitor cell
- > Eryhtroblast
- > Reticulocyte (blood)
- > Erythrocyte (blood)
78
How do neutrohils combat bacteria?
Phaocytosis
| Neutrophil extracellula traps (NETS)
79
Whena re eosinophils most abundant?
During allergic reaction
80
What is a cytokine?
A protein or peptide thats released from one cell type & acts on another
81
What 2 types o cytokines are involved in leukopoiesis?
Colony stimulating factors
| Interleukins
82
What is leukocytosis>
Increase in WBC number in blood
83
What governs platelet formation?>
Thrombopoietin
84
How does the haematocrit affet blood viscosity?
A 50% haematocrit increase doubles viscosity
85
How does temp affect viscosity?
A 1C increases in temp decreases viscosity by 2% and vice versa
86
How does cholesterol get into the membrane?
Inserts itself into the lipid layer
87
Where are carbs in the membrane & what do they do?
Glycoprotein & glycolipid on extracellular surface
| Self-vs-nonself recognition
88
Why does myelin have a tiny pritein content & inner mt membrane a lot?
In myelin protein is replaced by lipid for insulation of APs
| In mt inner membrane protein is required for energy transduction
89
Name some peripheral proteins & functions
G proteinsperform intracellular signalling functions
Collagen anchors cells to the ECM
Others join membrane & cytoskeleton
90
What are the main determinants of tonicicty in the ECF & ICF
ECF =Na+ & Cl-
| ICF = K+
91
In what cases does positive feedback occur as part of normal physiology?
- Ovulation
- Sexual behaviour
- Nerve AP
92
How is water distrivuted in a normal 70Kg young man?
28L in ICF
11L in ISF (~80% of ECF)
3L in plasma (~20% of ECF)
93
What compartments can be measured for fluid volume?
```
Only those of which plasma is a component:
Plasma
ISF
ECF
TBW
```
94
What are the criteria for a test substance when measuring fluid volvumes?
```
Non-toxic
Unchanged by body
Musnt affect distribution of water
Evenly distributed in measured compartment
Easy to measure
```
95
What do we use to measure plasma volume (PV)?
Dyes or radioactive labels attachedto plasma proteins
| E.g. Evans blue or I25 albumin
96
What can be used to measure ECF?
Needs to freely corss capilalry wall but not cell membrane:
| Na+ or Cl- that are actively excluded from cells
97
How do we measure TBW?
A loading dose of radioactive water
| E.g. Deuterium oxide or ehavy water
98
How do we determine the volume of ISF or ICF?
```
ISF = ECF - PV
ICF = TBW - ECF
```
99
How does determinin the volume of a compatement work?
- Inject the test substance
- Sample the fluid for test substance conc.
- calculate Vd by:
(amount injected - any excreted or metabolised) / conc.
[V=n/c]
100
What are the 3 types of fibrous joint?
- Suture
- Syndesmosis
- Gomphosis
101
What are the features of a synovial joint?
Always:
- Fibrous capsule
- Synovial membrane
- Articular cartilage
- Synovial Cavity
Sometimes:
- Bursae
- Ligaments
- Articular Discs
102
What is an anastomoses?
Where blood vessels branch alot then reconnect allowing multiple paths for blood to flow.
103
Where are anastomoses commonly found?
Around joint as during movement some of the vessels will be compressed so the blood needs multiple paths to flow
104
What is hiltons law?
A nerve supplying muscle that cross a joint will innervate the joint as well
105
What is craniosynostosis?
Premature closure of sutures in the skull resulting in abnormal skull growth.
106
What are hte outcomes of craniosynostosis?
Can be aesthetic
Can also affect brain development
Can incerase intercranial pressure leading to nerve damage and blindness etc
107
What are occludin junctions?
Includes tight junctions that seal gaps between epithelial cells preventing backflow of ions
108
What are the two cell-cell anchoring junctions?
Adherens connects actin filament bundles of adjacent cells
| Desmosomes connect intermediate-filament bundles of adjacent clels
109
What do desmosomes conenct?
Intermediate filaments such as keratin
110
What do adherens connecT?
Actin filaments (type of microfilament)
111
What do gap junctions allow?
Passage of small water soluble molecuels
112
How are cells linked to the matrix?
Using the intermediate filaments by hemidesmosomes
| Using actin filaments by actin linked adherenes
113
What do lysosomes do?
Seperate enzymes from the rest of the cell.
| Autophagy
114
What are ciia & flagella made of?
Microtubules from the cytoskeleton
115
Configuration vs conformation?
```
Configuration = fixed
Conformation = specific and convertable without breaking bonds
```
116
Difference between pyrimidine & purine?
Pyrimidine has a single ring
| Purine has a double ring
117
Exergonic/endergonic?
- Exergonic pathways are catabolic
| - Endergonic pathways are anabolic
118
What is an important buffer systemin cells?
The phosphate buffer system
119
What is an important buffer in plasma?
The bicarbonate buffer:
H2CO3 dissociates to HCO3-.
It absorbs pH changes caused by cellular products like lactic acid & ketone bodies.
120
What are the levels of muscle fibre?
Fibril
Fibre
Muscle
121
When does troponin move tropomyosin off the myosin binding site?
When bound to ca2+
122
Name the types of contraction
Isotonic - shortening
Lengthening - DUh
Isometric - No lenth change
123
Tension vs load?
Tension is force exerted by muscle
| Load is tension exerted on muscle
124
What is latent period>
Time between signal & start of contraction
| Isometric has the shortest
125
What is contration time?
Time between start of tension & peak tensoin
126
What changes with increased load?
The contraction velocity & distance
127
Whats the difference betwween fused & unfused tetanus?
Fused tetanus is a high & completely constatn contraction
Unfused is varying tension level within a certain range
128
What causes tetanus contraction?
Repeated stimulus maintiaing a high level of calcium
129
Why is fatigue useful?
It prevents us using up all our ATP & experiecning Rigor
130
What causes fatigue i high intensity exercise?
- Acidified proteins by lactic acid
- ADP + Pi inhibiting myosin detachment
- High [K] leads to depolaristion which causes conduction failure
131
Waht causes fatigue in low intensity xerceise?
Low glycogen
Low blood Glc
Dehydration
132
Other fatigue?
Central command Fatigue
| Cerebral cortex cant excite motor neurones
133
What causes atrophy?
```
Disuse atrophy
Denervation atrophy (nerve/NMJ damage)
```
134
How are filametns arranged differently in smooth msucle?
Diagonally across cells and anchored to membranes & cell structures
135
Smooth muscle cross bridge cycle:
- Ca2+ binds to calmodulin
- Ca2+/Calmodulin complex binds to Myosin light chain kinase
- Phosphorylates x-bridges with aTP
- Phosphorylated X bridges bind to actin &
- Myosin light chain phosphatase dephosphorylates X-bridges
136
How do we maintain smooth muscle tension for a long time with relatively little ATP use?
You can slow the cycle by phosphorylating x-bridges while still bound to actin
137
What is basal tone?
Basal level os smooth muscle contration graded by number of APs
138
What do pacinian corpuscles repsond to?
Vibration/stretch
139
Merkel receptors?
Texture/steady pressure
140
Meissners corpuscle?
Flutter & stroking movement
141
What is acuity?
The ability to locate a stimulus on the skin & differnetiate from others nearby.
Affected by convergence
142
Lateral inhibitio?
Pathway close to centre of a stimulus inihbits its neighbours allowing more precise localisation of the stimulus
143
How is the cortical body map distorted?
The most sensitive areas occupy the biggest space?
144
Langerhans cells?
Immune surveillance
145
How do hair follicles form?
Downgrowth of epithelial cells
Invasion of blood vessels
Hair growth
146
How does the arrector pili muscle work?
Attached to follicle root & base epidermis
| Contracts t straigten follicle
147
What does a sebacseosu gland do?
Releases sebum onto hair follicles for no apparent reason
148
What causes Body odour?
Protein rich secretion from apocrine sweat glands
149
What do eccrine sweat glands secrete?
a watery secreiton
