Science for Medicine Flashcards
1
Q
classification of disease
A
Growth
Unnatural
Degenerative
Developmental
Inflammatory
Circulatory
2
Q
Feed forward control
A
more sensitive form of negative feedback
sensors are involved so changes can be anticipated e.g. temperature regulation
3
Q
configuration
A
The fixed arrangement of atoms in a molecule. e.g. cis/trans
4
Q
Conformation
A
The precise arrangement of atoms in a molecule
5
Q
role of the cytoskeleton
A
provides strength and support, while also allowing for cell motility
6
Q
pH means
A
-log[H+]
7
Q
pH=
A
pKa + log[A-]/[HA]
8
Q
osmolality
A
The number of osmoles per kilogram of solvent
9
Q
desmosomes
A
cell-cell junctions provide firm anchorage
10
Q
Tight/occluding junctions
A
cell-cell junctions seal intercellular spaces
11
Q
gap junctions
A
cell-cell junctions allow for cell-cell communication
12
Q
Hemidesmosomes
A
cell-ECM junctions
13
Q
Hepatocytes
A
epithelial cells of the liver
14
Q
endocrine
A
secretes into the blood
15
Q
exocrine
A
secretes to the “surface”
16
Q
composition of the layers of the skin
A
epidermis - epithelium
dermis - connective tissue
hypodermis - fat
17
Q
papillary layer
A
top layer of dermis loose connective tissue blood vessels nerve endings
18
Q
Reticular layer
A
bottom layer of dermis dense irregular connective tissue
19
Q
composition of bone
A
protein: mostly type I collagen
minerals: Hydroxyapatite
20
Q
alpha helix bonds
A
H bonds between the N-H group and the C=O group in every 4th amino acid.
21
Q
beta sheet bonds
A
H bonds between the amide groups of linear polypeptide chains
22
Q
Tertiary structure interactions
A
van der Waals
ionic interactions
hydrogen bonding
disulphide bridges
hydrophobic interactions
23
Q
fate of absorbed galactose
A
phosphorylayed to galactose-1-phosphate
converted to gucose-1-phosphate
converted to glucose-6-phosphate
enters glycolysis
24
Q
fate of absorbed fructose
A
phosphorylated to form fructose-1-phosphate
converted to glyceraldehyde
phosphorylated again to form glyceraldehyde-3-phosphate (G3P) and enters glycolysis
25
functions of the pentose phosphate pathway
produces NADPH
produces pentose sugars needed for nucleic acid synthesis
metabolises any pentose sugars in the diet
26
phases of the pentose phosphate pathay
1. oxidative, irreversible part
- generates NADPH
- converts G-6-P to ribose-5-phosphate
2. non-oxidative reversible part
- interconverts between sugars
27
fluoroscopy
obtains moving images using x-ray
28
carnitine fatty-acyl CoA
enzyme that transports carnitine-FA across the inner mitochondrial membrane
inhibited by malonyl CoA so FA synthesis and degradation don't occur simultaneously
29
types of membrane receptors
receptors that act as ion channels
receptors with intrinsic enzyme activity
receptors that interact with JAK kinases receptors that interact with G-proteins
30
Andenylyl Cyclase pathway
g-protein linked receptor activates adenylyl cyclase.
Adenylyl cyclase is phosphorylated by ATP producing cAMP
cAMP activates cAMP dependent protein kinase A (PKA)
PKA can phosphorylate many proteins to regulate their function.
31
Phospholipase C pathway
g-protein linked receptor activates phospholipase C
phospholipase C converts PIP2 to IP3 and DAG
IP3 stimulates the endoplasmic reticulum to release Ca2+
Ca2+ and DAG activate protein kinase C (PKC)
PKC can phosphorylate many proteins to regulate their function.
32
laws of thermodynamics
energy can be converted between forms but not created or destroyed
all energy transformations lead to an increase in entropy
33
conduction velocity increases...
with fewer Na+ channels (opening them is time consuming)
there can be fewer channels in myelinated and wider axons as charge travels further up them
34
excitatory CNS neurotransmitters
acetylcholine
norepinephrine
dopamine
seratonin
histamine
glutamate
35
inhibitory CNS neurotransmitters
GABA
Glycine
36
recruitment of motor units
As load increases, more motor units are recruited to compensate
37
Slow oxidative muscle fibres
more mitochondria so more oxidative phosphorylation
more vascular so higher delivery of O2 and nutrients
contain myoglobin to help with O2 delivery
fibres are red and of low diameter
**Resist fatigue**
38
fast oxidative muscle fibres
more mitochondria so more oxidative phosphorylation
more vascular so higher delivery of O2 and nutrients
contain myoglobin to help with O2 delivery
fibres are red and of low diameter
**Intermediate resistance to fatigue**
39
fast glycolytic fibres
few mitochondria but high concentration of glycolytic enzymes and glycogen.
low blood supply
white fibres with low diameter
**Fatigue quickly**
40
ATP
a free energy carrier
couples anabolic and catabolic reactions
41
electron carriers used in redox reactions
NAD+
NADP+
FAD+
42
NAD+ is used...
In redox reactions of glycolysis, and the TCA cycle
43
NADP+ is used...
in anabolic reactions
e.g. fatty acid synthesis
44
osteoclasts are derived from
a haemopoietic lineage
45
osteoblasts are derrived from
a mesenchymal lineage
46
fates of glycogen in skeletal muscle and the liver
**Skeletal muscle:**
glycogen --\> glucose-1-phosphate --\>
glucose-6-phosphate --\> glycolysis
(forms ATP for muscle contraction)
**Liver:**
glycogen --\> glucose-1-phosphate --\>
glucose-6-phosphate --\> glucose
(enters the bloodstream to increase blood glucose concentration)
47
fate of dietary protein
**1.** denaturation of proteins by _HCl_
**2.** _pancreatic enzymes_ create a mix of free amino acids and free peptides
**3.** _membrane enzymes_ break everything down into di-/tri-peptides
**4.** all is absorbed into intestinal cells and completely broken down into free amino acids by _peptidses_
**5.** free amino acids enter the blood stream
48
primary lymphoid organs
thymus
bone marrow
foetal liver
where lymphocytes are generated
49
secondary lymphoid organs
Lymph nodes
spleen
where immune responses are initiated and lymphocytes maintained
50
digestion of dietary carbohydrates
1. salivary amylases in the mouth
2. pancreatic amylases in the duodenum
3. membrane enzymes in the jejenum
51
absorbtion of glucose
glucose is transported through glucose symport, driven by the concentration gradient of Na+ created by Na+/K+ ATPase.
glucose then enters the boodstream through glucose uniport, driven by its own concentration gradient.
galactose has a similar mechanism
52
absorption of sucrose
moves down its own concentration gradient through the cannel protein GLUT5
53
precursors for gluconeogenesis
lactate from excercising muscle.
oxaloacetate from proteins
54
Glutamate
only glutamate can obtain its nitrogen directly from NH4+ (ammonium ions). this reaction requires reduction of NADPH and breakdown of ATP.
glutamate can then transfer its amino groups to alpha-keto acids to form other amino acids
55
how is nitrogen transporthed through the blood?
as alanine or glutamine
| (amino acids that have no charge)
56
reasons for strength of bone
minerals (hydroxyapatite) - withstands pressure
collagen - withstands tension (a bit flexible)
57
protective roles of the skin
repair
waterproofing
chemical resistance
UV light penetration
termoregulation
immune protection
wear and tear
58
high affinity means
smaller concentration is needed to evoke the same response
59
sources of intracellular calcium
opening ion channelsto allow calcium to enter.
inhibition of calcium transport out of the cell.
released from internal stores in the endoplasmic reticulum, stimulated by IP3-
60
cutaneous receptors
sensory receptors found in the skin
61
purpose of propioceptors: muscle spindle and golgi tendon organ
**provide sensory info for...**
1. propioception + kinaesthesia
2. spinal reflexes
3. to inform voluntary movement from the brain
62
spindle discharge
**no. of APs fired**
decreases with contraction.
increases with relaxation.
63
Golgi tendon organ
monitors muscle tension.
muscle contraction = mors APs fired.
muscle relaxation = less APs fired
64
Stretch Reflex
**stimulus:** muscle is stretched
**receptor:** muscle spindle
**response:**
**1.** agonist contracts (monosynaptic reflex)
**2.** antagonist relaxes (inhibitory interneurones)
- reciprocal inhibition
**3.** info ascends to brain in dorsal collumns
65
inverse stretch reflex / clasp knife reflex/ golgi tendon organ reflex
**stimulus:** muscle contacts
**receptor:** GTO
**response:**
**1.** antagonist contracts (excitatory interneurones)
**2.** agonist relaxes (inhibitory interneurones)
**3.** info ascends to brain in dorsal collumns
66
flexor withdrawal reflex
**stimulus:** pain
**receptor:** nociceptors
**response:**
**1.** ipsilateral flexors and contralateral flexors contract (excitatory interneurones)
**2.** ipsilateral extensors and contralateral flexors relax (mixture of interneurones)
**3.** info ascends to brain in contralateral spinothalmic tract
67
ways in which enzymes catalyse reactions
**entropy reduction** - enzymes force substrate into correct orientation
**Desolvation** - bonds between enzyme and substrate replace H-bonds between substrate and solution
**Induced fit** - conformational changes in the enzyme put bonds under pressure
68
V0 (initial rate of reaction)
increases with substrate concentration
69
Vmax
maximum reaction velocity
occurs when all enzyme active sites are full
70
meaning of Vmax and Km
high Km = low affinity
high Vmax = high efficacy
71
competitive inhibition
active site is blocked so affinity is decreases = **increase in Km**
increasing substrate conc. means **the same Vmax can still be reached**
72
non-competitive inhibition
active site is not blocked so **Km is unchanged**
increasing substrate conc. doesn't change inhibition so **Vmax decreases**
73
covalent modification
e.g. phosphorylation
regulates many enzymes
74
average circulating volume in a typical adult male
5 litres
75
function of plasma proteins
**Albumin** = transport
**globulin** = transport and immunoglobulins
**fibrinogen** = clotting
76
erythropoietin
a hormone produced in response to hypoxia.
controls and accelerates erythropoietin.
produced in kidneys
77
Leukopoiesis (WBC formation)
controlled by a cocktail of cytokines that are released from endothelial cells, fibroblasts and mature WBCs.
cytokines stimulate mitosis and maturation of leukocytes.
78
thrombopoietin
regulates platelet formation
79
viscosity of plasma
1.8x thicker than water
80
viscosity of whole blood
3-4x thicker than water
81
antibody structure
**light chain** (V-shape)
**heavy chain** (Y-shape):
has a variable (top) region and a constant (bottom) region.constant region is the same in all antibodies from the same class.
82
protein I of electron transport chain
oxidises NADH to form NAD+ (2e-s enter protein)
passes 2 e-s to ubiquonone (Q) to from ubiquonol (QH2)
pumps H+ ions into the intermembrane space
83
protein II of electron transport chain
oxidises FADH2 to form FAD+
passes electrons to Ubiquinone (Q) forming ubiquinol (QH2)
84
protein III of electron transport chain
receives electrons from QH2 from proten I and II.
passes leectrons on to cytochrome C
pumps H+ ions into the inntermembranous space
85
protein IV of electron transport chain
receives electrons from cytochrome C.
passes electrons on to O2 forming H2O.
pumps H+ ions throgh to the intermembranous space
86
3 phases of beta oxidation
**Activation** (in cytosol)**:**
FA + CoA --\> AcylCoA
(uses breakdown of 2 ATP)
**Transport:**
carnitine shuttle
**Degradation:**
dehydrogenation, hydration, dehydrogenation.
AcylCoA --\> Acetyl CoA + FA chain (reduced by 2C)
87
FA degradation
**dehydrogenation:** reduction of FAD+
**Hydration:** H2O added
**dehydrogenation:** reduction of NAD+
**Thiolysis:**
product splits into acetylCoA and a FA chain
produces 12 ATP
88
fatty acid synthesis
**Elongation:**
acetylCoA + CO2 --\> Malonyl CoA
(involves the breakdown of ATP)
{loss of CO2}
**Reduction:** oxidation of NADPH
**Dehydration:** loss of H2O
**Reduction:** oxidation of NADPH
{loss of CoA}
produces a FA chain, longer by 2 C
89
location of fatty acid synthesis
Cytosol
90
TCA cycle
91
irreversible steps of glycolysis
glucose --\> glucose-6-phosphate
fructose-6-phosphate --\> fructose-1,6-bisphosphte
PEP --\> Pyruvate
\* all involve the breakdown or production of ATP
92
Glycogen synthesis
**1.** short chains of glucose are added to glycogenin
**2.** chains are extended by glycogen synthase
**3.** long chains are broken and branked by glucose branching enzyme
93
Glycogen degradation/ mobilisation
**1.** terminal glucose molecules removed, phosphorylated and released as glucose-6-phosphate
**2.** 3 of the 4 remaining molecules are reattched to the main chain
**3.** the last molecule is released as free glucose
94
1st nitrogen aquiring reaction
NH4 --\> carbamoyl phosphate
| (requires the breakdown of 2ATP)
95
2nd Nitrogen aquiring reaction
citrulline + **aspartate** --\> **arginosuccinate**
(requires breakdown of ATP to AMP)
the aspartate comes from a transamination reaction with glutamate and oxaloacetate (the carbon skeleton for aspartate)
96
Urea formation
**arginine** + H2O --\> **UREA** + ornithine
(arginine and ornithine are part of the urea cycle)
97
glutamine/ glutamate conversion
Glutamine + H2O \<--\> Glutamate + NH4
98
how does nitrogen enter the liver **mitochondria**
all dietary amino acids transfer their amino groups to alpha-ketoglutarate forming glutamate (and their carbon skeletons).
nitrogen enters the mitochondria in glutamate or glutamine (that has come directly from the blood)
99
NMJ activity
**1.** motor neuron AP reaches the presynaptic terminal
2. voltage gated Ca2+ channels open
**3.** Ca2+ stimulates Ach vesicles to move towards the synapse
**4.** Ach is released by exocytosis and diffuses accross the synapse
**5.** Ach gated Na+/K+ channels open
**6.** Na+ enters the cell and generates an endplate potential
**7.** voltage gated Na+channels open
**8.** Na+ enters the cell and an AP is generated
**\*** Ach is removed by acetylcholinesterase
100
skeletal muscle contraction
1. the AP causes the sarcoplasmic reticulum to release Ca2+ ions
2. Ca2+ binds to troponin which changes the conformation of tropomyosin
3. this allows myosin heads to bind to actin binding sites and make the muscle contract
4. to end contraction, Ca2+ is rapidly taken up into the sarcoplasmic reticulum by an ATPase
101
smooth muscle contraction
**1.** the AP opens voltage gated Ca2+ ion channels so extracellular Ca2+ ions enter the muscle cell
(some Ca2+ is also released from the sarcoplasmic reticulum)
**2.** Ca2+ binds to calmodulin, activating it
**3.** activated calmodulin activates myosin light chain kinase
**4.** activated myosin light chain kinase phosphorylates myosin heads allowing for muscle contraction.
102
Pacinian corpuscle structure
a cutaneous mechanoreceptor.
consists of an un myelinated nerve ending surrounded by connective tissue membrane lamellae with fluid in between the lamellae.
103
pacinian corpuscle action
**1.** a mechanical stimulus deforms the capsule
**2.** the nerve ending is stretched causing ion channels to open
**3.** Na+ enters the cell generating a receptor potential which generates an action potential.
**4.** fluid redistributes between the lamellae and APs stop firing until the stimulus is removed **(Adaptation)**
104
Nociceptors
free nerve endings.
detect painful stimuli.
do not adapt.
