Exam Flashcards
1
Q
3 places where single unit smooth muscle is found
A
- Digestive tract
- Urinary tract
- Reproductive tracts
2
Q
3 places where multi-unit smooth muscle is found
A
- eye muscles
- blood vessels
- pili muscles (skin)
3
Q
Describe the mechanism for excitation-contraction coupling in smooth muscle
A
Action potential or hormones can provide the rise in cytoplasmic Ca2+.
• Ca2+ binds to calmodulin
• The complex of Ca2+ and calmodulin together activates the enzyme MLCK (myosin
light chain kinase), which activates MLC (myosin light chain) via phosphorylation.
• This activates the cross-bridge.
4
Q
List the 4 somatic and visceral sensations
A
- Touch
- Warm/cold
- Pain
- Body position
5
Q
List the 5 special senses
A
- Taste
- Smell
- Hearing
- Vision
- Balance
6
Q
What are the three methods of information input into the CNS? Give an example
A
- Direct (e.g. temperature sensing in hypothalamus)
- Endocrine (e.g. control of food intake)
- Nervous
7
Q
What four types of information describe a sensory stimulus?
A
- Modality (type)
- Duration
- Intensity (frequency of AP firing)
- Location (of AP receptor)
8
Q
Where in the muscle are the length receptors used for proprioception found?
A
Muscle spindle
9
Q
Where in the muscle are the tension receptors used for proprioception found?
A
Golgi tendon organ
10
Q
What receptor adapt slowly? Rapidly?
A
Slow - stretch receptors
Rapid - touch receptors
11
Q
Describe the axons that nociceptors for fast/acute pain send signals through. What is the name for these fibres?
A
- Large, myelinated
- A fibres
12
Q
Describe the axons that nociceptors for slow/chronic pain send signals through. What is the name for these fibres? Fast/slow conduction?
A
- Small, unmyelinated axons.
- B fibres.
- Slow conduction
13
Q
Which of the following goes up and across? Which goes across and up?
- Somatic sensory – medial lemniscal (dorsal column)
- Somatic sensory– lateral spinothalamic (anterolateral)
A
- Up and across
2. Across and up
14
Q
What is the Somatic sensory – medial lemniscal (dorsal column) pathway for?
A
- Fine touch and proprioception
15
Q
What is the somatic sensory - lateral spinothalamic (anterolateral) pathway for?
A
- Pain
- Temperature
- Crude touch
16
Q
What is the somatic motor – pyramidal (corticospinal) pathway for?
A
Precise movement (hands and feet)
17
Q
In the withdrawal reflex, what happens ipsilaterally?
A
Interneurons and afferent neurons excite flexors, inhibit extensors.
18
Q
In the withdrawal reflex, what happens contralaterally?
A
Interneurons and afferent neurons excite extensors, inhibit flexors.
(Stabilise)
19
Q
Name the basal nuclei
A
- caudate nucleus
- amygdaloid
- lentiform nucleus
20
Q
Where do sympathetic pre-ganglionic neurons emerge from the spinal
cord?
A
Thoracolumbar levels
21
Q
Where do parasympathetic pre-ganglionic neurons emerge from the spinal cord?
A
Craniosacral levels
22
Q
What is the neurotransmitter for a cholinergic neuron?
A
ACh
23
Q
What is the NT for a adrenergic neuron?
A
NE
24
Q
Are parasympathetic neurons cholinergic or adrenergic?
A
Cholinergic
25
Are sympathetic neurons cholinergic or adrenergic?
Can be both
26
What type of receptor is ionotropic? What is the effect?
Nicotinic cholinergic - excitatory
27
Where is adrenaline released from? How is this area innervated by the autonomic nervous system?
- Adrenal medulla
| - Directly from first neuron in spinal cord (i.e. not via postganglionic neuron)
28
Name the CNS glia & their function
- Astrocytes: supply nutrients to neurons, ensheath blood capillaries, transmit info.
- Microglia: immune cells, engulf microorganisms and debris
- Ependymal cells: line fluid-filled spaces in brain and spinal cord, circulate CSF (cilia)
- Oligodendrocytes: form myelin sheath, support nerve fibres
29
What is the PNS glia? What's its function?
- Schwann cells; form myelin sheet, support peripheral nerve fibres
30
What are the 3 morphological types of neuron?
1. Multipolar
2. Unipolar
3. Bipolar
31
What are the 3 types of synapse?
1. Axodendric
2. Axosomatic
3. Axoaxonic
32
Where in the spine do sympathetic nerves exit from?
| Where do they synapse with the post-ganglionic neuron?
```
Thoracolumbar levels
Sympathetic ganglion (short distance from spinal cord)
```
33
Where in the spine do parasympathetic nerves exit from?
| Where do they synapse with the post-ganglionic neuron?
Craniosacral levels
| In ganglion in/near effector organs (far from spinal cord)
34
What are the 4 structures associated with the spinal cord?
1. Meningeal sack
2. Conus medularis
3. Filum terminale
4. Cauda equina
35
Where does sensory info enter the spinal cord?
In dorsal roots
36
Where does motor info leave the spinal cord? (Somatic & autonomic)
Through ventral roots:
- somatic in ventral horns
- autonomic in lateral horns
37
Where do spinal nerves go once they leave the spinal column?
Break into two branches: dorsal and ventral rami
| Ventral ramus communicates w/ sympathetic chain
38
Facial bones
- Zygomatic (x2)
- Maxillary (x2)
- Nasal (x2)
- Mandible
39
What are the 3 sutures of the skull? What bones do they separate?
1. Coronal (frontal-parietal)
2. Lambdoidal (parietal-occipital)
3. Squamous (Temporal-parietal)
40
What is the name for the gaps substituting for sutures in infants?
Fontanelles
41
What are the 3 dural reflections?
1. Falx cerebri (separates two hemispheres of cerebrum)
2. Falx cerebelli (separates two hemispheres of the cerebellum)
3. Tentorium cerebelli (separates cerebrum and cerebellum)
42
Circulation of the CSF in the ventricular system
Choroid plexus --> lateral ventricles --> third ventricle --> cerebral aqueduct --> fourth ventricle --> subarachnoid space
43
4 major sulci and fissures
1. Central sulcus (divides frontal and parietal lobes)
2. Parieto-occipital sulcus
3. Lateral sulcus (perpendicular to central sulcus)
4. Transverse fissure (gap b/w cerebrum & cerebellum)
44
2 major gyri
1. Pre-central gyrus
| 2. Post-central gyrus
45
What are the two divisions of the motor cortex and how are they involved with voluntary movement?
1. Pre-motor cortex: planning of movement
| 2. Primary motor cortex: execution of movement
46
What are the 4 major divisions of the brain and what structures do they include?
1. Cerebrum
2. Diencephalon: thalamus and hypothalamus
3. Cerebellum
4. Brainstem: Mid-brain, pons, medulla oblongata
47
Three types of white matter (tracts) in the brain
1. Commissural tracts (side to side)
2. Projection tacts (extend from motor cortex)
3. Association tracts (same side)
48
Corticospinal tract:
- Controls?
- Where are cell bodies?
- Where does it cross over?
- Where does it synpase?
- Controls somatic motor neuron
- Cell bodies in primary motor cortex
- Cross in medulla
- Synapse in ventral horn of spinal cord
49
Simple somatic sensory pathway:
- Ascends in?
- Synapse in?
- Cross where?
- Second synapse?
- Terminates in?
- Ascends dorsal white columns
- Synapse in medulla
- Up and across
- Synapse in thalamus
- Ends in somatosensory cortex
50
What are the 5 nuclei that make up the basal ganglia?
- Caudate
- Putamen
- Globus pallidus
- Subthalamic nucleus
- substantia nigra
51
What are the concentrations of Na+ and K+ inside and outside the cell?
Inside: Na+ 12mM & K+ 150mM
Outside: Na+ 142mM & K+ 4mM
52
What does the sodium potassium pump move b/w the cell membrane?
2 K+ in
| 3 Na+ out
53
What are the 3 ways the synapse is switched off? Why does this occur?
Excess transmitter into cleft; removed by:
- Degradation by enzymes
- Reuptake into the bouton
- Reuptake into glia
54
Types of neurotransmitters (and excitatory or inhibitory)
- ACh; excitatory
- NE; inhibitory or excitatory
- Glutamate; excitatory
- GABA; inhibitory
55
Divergent networks
- Info from pre-synaptic cell diverges to activate 2+ post-synaptic neurons
- Allows a single signal to arrive at multiple brain regions
- Amplifies signal
56
Convergent networks
- Info from different brain regions converge to activate only 1 post-synaptic motorneuron (that excites a single muscle group)
- Allows redundancy
57
Function of the 3 types of muscle (skeletal, cardiac and smooth)
Cardiac - pump blood
Smooth - movement of fluids
Skeletal - generate heat, posture, movement
58
What are the thin and thick myofilaments?
Thin: actin, troponin, tropomysin
Thick: myosin, myosin heads
59
What is the mechanism for contraction? State the important parts of each step.
1. Excitation: AP reaches bouton; Ca2+ entry; release of ACh; depolarisation of sarcolemma; initiation of AP
2. Contraction: Ca2+ release from SR; cross bridge formation (actin and myosin); contraction
3. Relaxation: Ca2+ reuptake; uncoupling of crossbridge
60
How long is the contraction for ATP? CP?
ATP: 2-4s
CP: approx. 20s
61
What are the 3 types of muscle fibres? Why are the coloured?
1. Red; high myoglobin; high aerobic enzymes
2. White; low myoglobin; low aerobic enzymes
3. Intermediate; mixture; aerobic and anaerobic
62
Compare the muscle fibre types (in terms of rate of interaction w/ actin and force production)
1. Red (Myosin type I): slow rate & slow force production & slow energy consumption
2. White (Myosin type IIx): fast rate & fast force production & fast energy production
3. Intermediate (Myosin type IIa); mixture
63
Difference b/w physiological fatigue and psychological fatigue
- Physiological: ATP depletion, buildup of by-products
| - Psychological: feedback to brain producing sensation of fatigue
64
Structure of the 3 types of muscle
Cardiac: striated, intercalated discs, branched
Skeletal: striated, thin, cylindrical,
Smooth: non-striated (net)
65
Smooth muscle contraction
- AP or hormones provide Ca2+ rise
- Ca2+ binds to calmodulin
- Ca-calmodulin complex activates MLCK
- MLCK activates MLC which activates the crossbridge
66
Afferent pathway for touch and posture (dorsal column pathway):
- How many neurons in relay?
- Cross immediately or delayed?
- Starts and ends?
- 3 neurons
- Up and across
- Primary sensory neuron --> somatosensory ortex
67
Afferent pathway for pain (anterolateral pathway):
- How many neurons in relay?
- Cross immediately or delayed?
- Starts and ends?
- 3+ (can have interneurons)
- Across and up
- Primary sensory neuron --> somatosensory cortex
68
Somatic control (What does it control? Same pathway or different?)
- Control of skeletal muscle
- Reflex movements
- Precise, voluntary movements
- Autonomic movements
> All via a final common pathway
69
What two things occur simultaneously during a withdrawal reflex?
1. Withdrawal from stimulus
| 2. Opposite side of body is activated to reverse the effect of withdrawal (stabilise)
70
Corticospinal pathway (pyramidal tract):
- Controls?
- How many neurons?
- Crosses over where?
- Starts and ends where?
- Fine control of the digits
- 2 neurons
- Crosses over at medulla
- Primary motor cortex --> effector
71
Somatic vs autonomic efferent pathway:
- how many neurons b/w CNS and effector
- what muscle does it innervate?
- excitatory or inhibitory?
- 1 (S) vs. 2 (A)
- Skeletal muscle (S) vs. Smooth muscle, cardiac muscle, glands (A)
- Excitatory (S) vs. excitatory or inhibitory (A)
72
Where do sympathetic and parasympathetic neurons emerge from (in the spinal cord)
Sympathetic: thoracolumbar levels
Parasympathetic: craniosacral levels
73
Ionotropic receptors
- receptors contain an ion channel
- nicotinic cholinergic (releases ACh)
- Depolarising and excitatory
74
Metabotropic
- receptors linked to intracellular messengers
- muscarinic cholinergic
- adrenergic (releases NE)
- excitatory or inhibitory
75
What are the major endocrine glands? (6 - not including reproductive)
1. Hypothalamus
2. Pituitary gland
3. Thyroid gland
4. Adrenal glands (2)
5. Pancreas
76
Main steps for cellular response to water-soluble hormones
1. Hormone binds to receptor in cell membrane
2. Receptor activates associated protein
3. Protein activates enzyme
4. Second messenger produced
5. Second protein activated
6. second enzyme activated
7. Enzyme converts substrate to product (cell's response)
77
Main steps for cellular response to lipid-soluble hormones
1. Hormone dissociates from carrier protein
2. Diffuses through cell membrane
3. Binds to receptor in cytoplasm
4. Hormone-receptor complex acts as transcription factor
5. New mRNA generated
6. New protein generated
7. Protein mediates specific response
78
Compare the storage of the two types of hormone
Water soluble: stored until required
| Lipid soluble: Made as required (except for thyroid hormone)
79
Compare the fed state and fasting state
Fed state: anabolism, uptake of nutrients; synthesis/storage of glycogen, protein and fat
Fasting state: catabolism, breakdown of nutrients, breakdown of glycogen, protein and fat
80
What hormones maintain the blood glucose concentration? What is the reference range?
- Insulin (decreases) and glucagon (increases)
| - 3.5-6mM
81
Type I diabetes:
- cause
- symptoms
- treatment
- diagnosis age
- Beta cells destroyed --> low/no insulin
- high blood glucose conc. (hyperglycaemia), glucose in urine (glycosuria), polydipsia, polyphagia, polyuria
- Insulin injections & trialling human/pig islet transplantation
- Young/childhood (usually)
82
Type II diabetes
- cause
- symptoms
- treatment
- diagnosis age
- Insulin resistant cells --> low insulin levels
- high blood glucose conc. (hyperglycaemia), glucose in urine (glycosuria), polydipsia, polyphagia, polyuria
- drugs promoting insulin release, exercise, sometimes insulin injections
- Used to be an adult disease, but more prevalent in kids
83
What can hyperglycaemia cause over time? (e.g. diseases)
- Atherosclerosis (can lead to heart attack, stroke)
- Blindness
- Nerve damage
- kidney disease
84
What happens when bg conc. decreases?
- Alpha cells secrete glucagon
- Liver cells: increase glycogenolysis, increase gluconeogenesis, increase ketone synthesis
- bg conc. increases
- negative feedback
* note: GH, adrenalin and cortisol also increase bg level
85
What happens when bg conc. increases?
- Beta cells secrete insulin
- Liver cells: decrease glycogenolysis, decrease gluconeogenesis, decrease ketone synthesis
- bg conc. decreases
- negative feedback
86
Posterior pituitary:
- What hormones does it release?
- What do these hormones do?
- How does it communicate w/ the hypothalamus?
- Releases ADH and oxytocin
- ADH stimulates water reabsorption, and oxytocin causes uterine muscles to contract during childbirth & stimulates milk release in breastfeeding
- Communicates via neurons
- Made in the hypothalamus and stored at the end of the neurons
87
Anterior pituitary:
- What hormones does it release?
- What do these hormones do?
- How does it communicate w/ the hypothalamus?
- Where are the hormones made?
- ACTH, GH, TSH
- GH promotes growth of muscle, bone and other tissues (stimulates cell division), ACTH stimulates the secretion of cortisol, TSH stimulates the secretion of TH
- Communicates via hormones (connected by blood vessels)
- Made in the anterior pituitary
88
What are the growth hormone disorders?
Dwarfism (deficiency) and gigantism (excess)
89
Adrenal glands:
| - What (2) glands are they made up of?
Adrenal cortex and adrenal medulla
90
What is secreted by the middle and inner layer of the adrenal cortex?
What is secreted by the adrenal medulla?
Inner: androgens
Middle: cortisol
AM: mainly adrenalin
91
What are the effects of cortisol? What response is it released for?
Stress response:
- Increases blood glucose (via gluconeogenesis)
- Increases blood pressure
92
What is the pathway for cortisol secretion? (incl. stimulus)
1. Stress or non-stress neural inputs
2. Hypothalamus secretes CRH
3. Anterior pituitary secretes ACTH
4. Adrenal cortex secretes cortisol
93
What are the 2 cortisol imbalance disorders? What are they caused by?
1. Addison's disease: too little cortisol
| 2. Cushing syndrome: too much cortisol
94
What does the adrenal medulla secrete?
Adrenalin
95
What hormones are secreted by the thyroid gland? Where are they made?
- Thyroid hormone
- Calcitonin
- Made in follicular cells
96
Briefly describe thyroid hormone synthesis
- TGB released into follicle (by follicular cells)
- Iodine reacts w/ TGB
- Iodised TGB moves into the follicular cells
- Thyroid hormones detach from TGB as needed
97
What are the disorders caused by thyroid hormone imbalance?
- Grave's disease: too much
- Myxedema: too little (in adults)
- Cretinism: too little (in newborns)
98
What is the name of the iodine deficiency disorder? Why does it occur?
Goitre; thyroid gland unable to produce enough TH
99
What are the hormones involved in Ca regulation?
Calcitonin and PTH
100
When does hypocalcaemia occur?
Conc. of Ca2+ in blood too low
101
When does hypercalcaemia occur?
Conc. of Ca2+ in blood too high
102
Chronic problems due to no insulin
- cardiovascular disease
- Renal failure
- retinal damage
- poor wound healing
- peripheral nerve damage
103
Screening for DM:
- What glucose level/range is suggestive of DM?
- What are the 2 tests?
- If >7mM, suggestive of DM
- Oral glucose tolerance test: 75g consumed and BGL measured; if >11.1 after 2h = DM (non-pregnant)
- HbA1c; used to access how well DM is being managed (HbA1c reflects the av. BG conc.)
104
What homeostatic mechanism(s) occurs after haemorrhage? (Incl. effect on blood pressure)
- Drop in bp detected by sensors (baroreceptors) in large arteries
- Info. sent to brainstem (integrator) via nerves
- nerve impulses sent from brain to heart to inc. HR and F of contraction // also sent to blood vessels --> constrict
- Result = increased BP
105
What is the immune system?
An organised system of organs, cells and molecules that interact together to defend the body against disease.
106
Organs of the immune system & whether they're primary or secondary
- Thymus (p)
- Bone marrow (p)
- Tonsils (s)
- Lymph nodes (s)
- Spleen (s)
107
Primary lymphoid organ vs. secondary
- Primary: production of lymphocytes (WBCs)
| - Secondary: sites where immune responses are initiated
108
Thymus
- Place where T cells develop mature ('school' for WBCs)
109
Bone marrow
- Source of stem cells that develop into cells of the innate and adaptive immune responses
110
Spleen
Site of initiation for immune responses against blood-borne pathogens
111
3 Layers of immune defence
1. Physical and chemical
2. Arm 1 (innate)
3. Arm 2 (adaptive)
112
Innate immune system characteristics
- rapid
- non-specific
- fixed
- no memory
- already in place
113
Adaptive immune system characteristics
- slow
- highly specific
- variable (changes)
- long-term memory
- improves during the response (teaches T cells)
114
Physical barrier: Structure of the skin (w/ description)
1. Epidermis: dead skin cells, keratin, phagocytic immune cells; constantly renewed; tightly packed
2. Dermis: thick layer of connective tissue, collagen, blood vessels and phagocytic immune cells
3. Contains DCs (which phagocytose and alert immune system)
115
Chemical barriers
1. Antimicrobial peptides (AMPs, e.g. defensins): form holes in invading microbial membranes --> microbes lose essential nutrients and ions --> die
2. Lysozymes: break down bacterial cell wall
3. Sebum: fatty secretion from hair follicle; low pH --> prevents microbial colonisation
4. Salt: creates hypertonic environment --> dehydrates microbes
116
Mucous Membranes
- line parts of the body that lead to outside & are exposed to air (ocular, respiratory, oral, urogenital)
- epithelium contains mucus-producing goblet cells
117
Mucociliary escalator
- Mucus traps foreign material
| - cilia move the mucus layer (and watery layer) --> removes foreign matter
118
GI tract characteristics (defence against pathogens)
- low pH (in stomach)
- Bile (in gall bladder)
- Digestive enzymes (in intestine)
- Mucus (traps microbes)
- Defensins (holes in microbes --> death)
119
What defence do the eyes use?
Tears:
- Contain lysozymes
- Flushing action
120
Urogenital tract characteristics (defence against pathogens)
- Flushing action (urine flow)
- lysozymes
- low pH
- High osmolarity (prevents microbial growth)
121
What are the 3 blood cell lineages? (Incl. examples)
| What/where are they derived from?
- Derived from stem cells in the bone marrow
1. Lymphoid (B & T lymphocytes)
2. Erythroid (RBCs (erythrocytes))
3. Myeloid (granulocytes, monocytes, DCs, platelets)
122
Granulocytes in blood: function & examples
- circulate in the blood & move into tissue during inflammation
- Neutrophils: eat & kill (phagocytose)
- eosinophils: release toxic granules
- basophils: release granules that mediate allergic reactions or fight worm infection
123
Granulocytes in tissue: function & example
- release granules that attract WBCs to areas of tissue damage
- e.g. mast cells
124
Monocytes
- Present in blood --> Low phagocytosis
| - Develop into macrophages when they leave the blood and enter tissue (spleen, liver) --> High phagocytosis
125
Macrophages (function)
- Become resident or move thr' tissues
| - Functions: phagocytosis, release of chemical messengers, show info about pathogenic microbes to T cells
126
DCs
- Found in low numbers
- Phagocytic
- Most important cell type to help trigger adaptive immune responses
127
Inflammation characteristics
1. Heat
2. Swelling
3. Pain
4. Redness
128
Fever (what happens)
- Temp >37 degrees
- Resetting of thermostat by hypothalamus
- Pyrogens (make us warm/hot)
- Phagocytes produce their chemical messenger and pyrogen IL-1 after ingesting bacteria
- Reduced phagocytosis = reduced IL-1 = reduced temp
129
Stages of the inflammatory response
1. Damage --> mast cells release cytokines (histamines, prostaglandins, and leukotrienes) --> vasodilation and vascular permeability
2. Neutrophils move out of blood capillaries and into tissue
3. Phagocytosis of pathogens; pussy lesion
130
What is type 1 IFN & what does it do?
- Innate antiviral protein // cytokine
- Combats viruses in 3 ways:
1. Signals neighbouring uninfected cells to reduce destroy RNA and reduce protein synthesis
2. Signals neighbouring infected cells to undergo apoptosis
3. Signals immune cells
131
What are TLRs and what do they do/cause?
- Pattern recognition receptors in/on innate cells
- Bind to microbes and drives the following immune mechanisms:
1. Phagocytosis
2. Cytokine release
3. IFN release
(I.e. elicit signals that drive inflammation)
132
What are the stages of phagocytosis?
1. Pseudopodia surround microbes
2. Microbes adhere to phagocyte & are engulfed
3. Ingestion of microbes into phagosomes
4. Fusion of phagosome and lysosome
5. Killing and digestion of microbe
6. Elimination via exocytosis
133
What are the 3 complement pathways?
1. Classical (antibody bound to pathogen binds complement)
2. Alternative (Pathogen binds complement to surface)
3. Lectin (carbohydrate components of microbes bind complement)
134
What do all 3 complement pathways produce? What are the 3 outcomes of this enzyme?
- C3
| - Either label (C3b), destroy (C9) or recruit (C3a and C3b)
135
What is opsonisation, recruitment and destruction?
- O: Coating of microbe with antibody or complement fragment (C3)
- R: Phagocytes attracted into site, mast cells degranulate, inflammatory mediators released
- D: microbes coated w/ C3 (opsonised) are phagocytose, assembly of MAC --> cell lysis
136
What are the 2 types of MHC? Where are they expressed?
1. MHC-I; antigens from w/in (i.e. viruses); expressed on all nucleated cells
2. MHC-II; antigen from outside (i.e. bacteria); expressed only on antigen-presenting cells
137
What are the steps of MHC-I antigen processing?
1. Antigen proteins degraded into peptides in the cytoplasm
2. Peptides imported to ER
3. Peptide loading of MHC-I takes place in ER
138
What are the steps of MHC-II processing?
1. Antigen enter via phagocytosis
2. Antigen proteins degraded in acidic phagolysosome
3. Peptide loading of MHC-II takes place in phagolysosome
139
How are unique TCRs produced (in the thymus)? What do they recognise?
- Immature T cells contain TRC genes in gremlin state
- TCR genes rearrange randomly
- mature (naive) T cells express unique TCR
- -------------
- Recognise peptide + MHC (together)
140
What does the CD4 T helper cell recognise? What is its role?
- Recognises MHC-II + peptide
| - Releases cytokines (activates CD8)
141
What does the CD8 T cell recognise? What is its role?
- Recognises MHC-I + peptide
| - Develops into cytotoxic T cell (which recognises virally infected cells & induces apoptosis)
142
What do NK cells kill?
Cells w/ low or no MHC-I
143
What do B cells recognise? How are they activated? What 2 cell types are created once activated?
- Recognise whole protein antigens (not peptides)
- Activated by: recognition of antigen AND CD4 help (both must occur)
- Plasma cells and memory B cells
144
What are the 3 functions of an antibody?
- Neutralisation: blocks microbes' ability to attach to host cells
- Opsonisation: binds to pathogen surface & facilitates uptake by phagocytes; clump bacteria together to inc. efficiency of phagocytosis
- Complement activation: binds to pathogen surface, activates C' pathway, C' proteins from MAC ---> cell death (hole)
145
What is isotype switching with regards to antibodies?
The mechanism that changes B cells' production of antibodies from one type to another (IgM/IgD, IgG, IgA, IgE)
146
What are the (5) different classes of antibody? (Inc. distribution and function)
1. IgG; most abundant in blood; opsonises/neutralises, crosses placenta, targets virus/bacteria
2. IgA; present in secretions (tears, saliva, mucus, breast milk); defence of mucus membranes, passive immunity, targets virus/bacteria
3. IgM; first Ig class produced after initial exposure to antigen, expressed on naive B cells; activates complement, acts as BCR, targets extracellular bacteria
4. IgE; present in blood in low conc.; immunity to multicellular parasites, allergic reactions, activates mast cells
5. IgD; expressed on naive B cells; act as BCR, specific function unknown
147
Do memory cells secrete antibody?
No
148
Compare primary and secondary immune response
- Primary: slow, low amount of antibody (IgM) produced
| - Secondary: fast, sufficient antibody (IgG) produced to eliminate pathogen
149
What are the 4 characteristics of innate immunity?
1. Rapid (hours)
2. Non-specific
3. No memory
4. Important in our response against extracellular pathogens (e.g. bacteria)
150
How do AMPs function? Where are they in the body?
- In skin, airways and gut
- bind to bacterial membranes (electrostatic interactions) & disrupt the membrane and its function (particularly effective against gram -ve)
151
How do lysosomes function? Where are they in the body?
- Skin and airways
- break NAG-NAM bonds b/w the glycopeptides of cell walls (outer layer of peptidoglycan) (particularly effective against gram +ve)
152
What are the 3 ways microbes can avoid the innate immune response?
1. Make surface molecules that resist AMPs
2. Evade uptake by encasing in a slimy capsule
3. Prevent fusion of phagosome w/ lysosome during phagocytosis
153
What are the 4 characteristics of adaptive immunity?
1. Slow (days)
2. Specific
3. Has memory
4. Important in our response against intracellular pathogens (e.g. viruses)
154
What are the 5 phases of the adaptive immune response?
1. Recognition of antigen by specific lymphocytes
2. Activation of lymphocytes (replication and differentiation into effector cells)
3. Elimination of antigen
4. Response declines as antigen is eliminated and most of the antigen-stimulated lymphocytes die (apoptosis)
5. Memory - surviving antigen-specific cells are responsible for memory
155
How do Cytotoxic T cells (CD8 cells) kill viruses?
- Internalised viruses have bits that are captured by the cell, which are presented on MHC-I by infected cells; this lets cytotoxic T cells know they're infected
- CD8 cells synthesise special proteins that specifically kill the virally infected host cell (perforin (makes a hole in the cell) and granzymes (move thr' the hole and induce apoptosis)
156
What is the process of B cells becoming plasma cells?
1. Antigen attaches to the BCR
2. CD4 attaches to antigens (presented by B cell MHC-II)
3. Cytokines released by CD4
4. Cytokines help B cells grow and develop into plasma cells
157
Briefly describe the specificity and memory of adaptive immunity
- Specificity: different antigens induce the production of different antibodies // also secondary response differs from primary response
- Memory: secondary response is more rapid and larger than the primary response
158
What do vaccines do?
Help prime the immune response for future exposure to a viral pathogen
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What are the 2 components of a vaccine? What is their role?
1. Antigen: the specific molecule that the immune system may recognise
2. Adjuvant: helps enhance the immune response against the antigen (stimulates the body into thinking it's a real infection).
160
What does the extracellular matrix contain?
- Water
- Proteins: collagen (strength), elastin (elasticity)
- Proteoglycans
161
How is the water divided in the body?
- ECF is 1/3 (4/5 ISF and 1/5 plasma)
| - ICF is 2/3
162
What is the reference range for Sodium in the ECF?
135-145mM
163
What are the fasting and non-fasting reference ranges for glucose (in ECF)?
Fasting: 3.5-6mM
| Non-fasting: 3.5-8mM
164
What is the reference range for Calcium in the ECF?
2.2-2.6mM
165
What is the reference range for Potassium in the ECF?
3.5-5mM
166
Normal pH range?
7.35-7.45
167
Normal temp range?
36-37.5 degrees
168
4 Types of membrane transport
- Facilitated diffusion: leak channels (spontaneous), ligand-gated (chemicals) and voltage gated
- Diffusion
- Active transport
- Exocytosis and endocytosis
169
Osmolarity
No. of particles (solute) in solution
170
Tonicity
Effect on cell vol.
171
Negative feedback
Oppose the change; move back to set point
172
Positive feedback
Move variable even further away from set-point
173
Feed-forward
Pre-emptive
174
4 key components of homeostatic control systems and what they do
1. sensor: monitors actual value
2. Integrator: compares actual and set-point
3. Effector: Produce response that restore variable
4. communication pathways: carry signals
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4 ways heat is transferred
1. Radiation
2. Conduction
3. Convection
4. Evaporation
176
What is the anatomical position?
- Upright
- Palms facing forward
- feet together
- face forwards
- --> same regardless of position
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What are the terms of direction?
- Superior
- Inferior
- Anterior
- Posterior
- Distal
- Proximal
- Deep
- Superficial
178
What are the planes of the body?
- Coronal
- Sagittal
- Transverse
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What are the movements of the body?
- Flexion
- Extension
- Abduction
- Adduction
- Circumduction
- Plantarflexion
- Dorsiflexion
- Rotation (lateral and medial)
- Pronation
- Supination
- Inversion
- Eversion
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5 Functions of the skeleton
1. RBC formation
2. Support
3. Storage
4. Movement
5. Protection
181
What are the functions of the two types of bone tissue and where are they found?
1. Compact: strength and load bearing; in diaphysis of long bone and surface of flat bone
2. Cancellous: shock absorption; in epiphysis of long bone
182
What are the 4 bone classes?
1. Long bones
2. Short bones
3. Flat bones
4. Irregular bones
183
What are the 2 divisions of the skeleton? What bones make them up?
1. Axial: skull, vertebral column and thoracic cage
| 2. Appendicular: Upper limbs (arms, forearms, hands) and lower limbs (thighs, legs, feet)
184
What is the main function of the lower limbs? Upper limbs?
Lower: stability and movement
Upper: manipulation
185
What are the two extracellular components of connective tissue & what are they composed of?
1. Organic material (33%)
- Resists tension
- Mainly collagen w/ proteoglycan foundation
2. Inorganic material (67%)
- Resists compression (provides hardness/support)
- Made up of hydroxyapetite (mineral salts)
186
What are the types of cells in bone & what are their main roles?
- Osteoblasts; build bone (& destroy cartilage --> bone)
- Osteoclasts: break down bone/ECM
- Osteocytes: mature bone cells trapped in lacunae
187
What is an osteon? What is its function?
- Subunit of compact bone; longitudinal; central canal (containing blood vessels) surrounded by sheets of lamellae
- Provide nutrients to cells
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What are lamellae?
tubes of ECM that from the osteon
189
What are lacunae?
Lakes for osteocytes; located b/w lamellae
190
What are canaliculi?
Channels in the ECM which connect lacunae; aids in diffusion b/w cells
191
What occurs at the periosteum?
- Osteoblasts are formed (for remodelling bone)
192
What is the structure of cancellous bone?
- Formed of trabeculae (struts of lamella bone) structured in different directions (max. shock absorption)
- Cavities filled w/ marrow
193
What is ossification and where does it occur?
- Cartilage to bone
- Primary centre: diaphysis
- Secondary centre: epiphysis
194
What are the 4 stages of a fracture?
1. Haematoma formed (blood clot)
2. Cartilaginous callous (fibroblasts form collagen fibres)
3. Bony callous (osteoblasts: cartilage to bone)
4. Remodelling
195
What are the 3 types of fracture?
1. Open (breaks thr' skin)
2. Closed (doesn't break thr' skin)
3. Greenstick (fracture doesn't go completely thr' bone)
196
What are the two types of cartilage? Incl. their main function
1. Articular/hyaline cartilage
- provides smooth, frictionless surface (high water content)
2. Fibrocartilage
- resists compression and tension
- e.g. meniscus
197
What are ligaments and tendons composed of? What is their function?
- DFCT
| - Resist tension
198
What do ligaments join? What do they do (regarding movement)?
- Bone to bone
| - Restrict movement
199
What do tendons join? What do they do (regarding movement)?
- Bone to muscle
| - Facilitate and control movement
200
What are the structures in a synovial joint?
- Synovial membrane
- Capsule
- Articular cartilage
- Cavity
- Ligament
201
What is range of motion determined by?
1. Bone end shape
2. Ligament location and length
3. Body surface contact
202
What are the 7 synovial joints? What movement direction(s) do they allow? Give an example for each.
1. Condylar; biaxial - flexion/extension, rotation; e.g. knee, TMJ
2. Hinge; uniaxial - flexion/extension; e.g. ankle, elbow, interphalangeal joints
3. Ellipsoid; biaxial - flexion/extension, abduction/adduction circumduction; e.g. wrist (radiocarpal)
4. Pivot; uniaxial - rotation; e.g. radioulnar joints (distal and proximal)
5. Saddle; biaxial (+) - flexion/extension, abduction/adduction, opposition, circumduction; carpometacarpal joint (wrist)
6. Ball and socket; multiaxial; flexion/extension, abduction/adduction, circumduction, rotation; e.g. shoulder, hip
7. Plane; multiaxial - sliding/gliding, flat articular surfaces; e.g. intercarpal and intertarsal joints
203
3 Types of joints & example of each
1. Fibrous; DFCT, limited movement and stability; e.g. cranial sutures, distal tibiofibula joint
2. Cartilaginous; fibrocartilage; some movement; e.g. intervertebral discs, pubic symphysis
3. Synovial; tissues and structures; free-moving; e.g. limb joints, b/w ribs and thoracic vertebrae
204
4 Functions of skeletal muscle
1. Movement
2. Heat production
3. Posture
4. Communication
205
Structure of myofibre
myofibre --> myofibril --> sarcomere --> myofilaments (thick and thin proteins)
206
What 3 factors determine the force of a muscle contraction?
```
Muscle fibre:
1. Length (inc. = inc. ROM)
2. Quantity (inc. = inc. force)
3. Arrangement (unipennate, bipenne, multipennate)
Motor unit:
1. Size
2. Number
3. Rate of firing
```
207
How does the motor neuron:muscle fibre ratio influence the movement of a muscle?
- Less muscle fibres = more precise
| - More muscle fibres = large movement
208
What are the 3 types of anatomical levers and their function?
1. Axis in middle; stabilises joint position (e.g. neck supporting head)
2. Load/weight in middle, pivot point at end; overcomes loads (e.g. calf muscle during calf raises)
3. Axis on end (and load on other end); large ROM (e.g. bicep curls)
209
What are the 3 types of muscle action? What happens to the muscle for each?
1. Concentric: muscle shortens
2. Isometric: muscle stays the same length
3. Eccentric: muscle lengthens
210
What are the 4 types of muscle role? What is the muscle action for each?
1. Agonist; acts concentrically
2. Antagonist; acts eccentrically
3. Stabiliser; acts isometrically
4. Neutraliser; muscle acts to eliminate unwanted movement
211
Deltoid: action(s) and attachment site(s)
- abduction, extension, flexion
| - pectoral girdle (scapula and clavicle) and humerus
212
Biceps brachii: action(s) and attachment site(s)
- Flexion at elbow, supination at radioulna
| - scapula (2 different sites) and radius
213
Triceps brachii: action(s) and attachment site(s)
- Extension at elbow
| - scapula and humerus (2 sites) and ulna
214
Iliopsoas: action(s) and attachment site(s)
- Flexion at hip
| - psoas & iliacus and femur
215
Gluteus maximus: action(s) and attachment site(s)
- Extension at hip
| - sacrum & pelvis and large tendon & femur
216
Quadraceps femoris: action(s) and attachment site(s)
- extension at knee
| - pelvis & femur and patella tendon --> tibia
217
Hamstrings (hip): action(s) and attachment site(s)
- extension
| - pelvis & femur and tibia & fibula
218
Hamstrings (knee): action(s) and attachment site(s)
- flexion at knee
| - pelvis & femur and tibia and fibula
219
Tibialis anterior
- dorsiflexion
| - tibia and medial tarsals
220
Triceps surae (gastrocnemius and soleus): action(s) and attachment site(s)
- Plantarflexion
| - femur, tibia & fibula and calcaneus
221
4 steps to muscle contraction
1. AP passes down a neuron to the NMJ
2. SR releases Ca2+ into myocyte
3. Ca2+ binds to troponin, which allows actin and myosin to bind (via tropomyosin binding sites on actin)
4. Contraction results
222
Conc. of K+ in ICF
150mM
223
Conc. of Na+ in ICF
10mM
224
Conc. of Na+ in ECF
135-145mM
225
Conc. of K+ in ECF
3.5.5mM
226
What is central tolerance?
Tolerance to self antigens: -
- Lymphocytes that recognise self antigens are destroyed tp prevent autoimmune disease (occasionally B cells edit their specificity to not longer be self-reactive)
227
Why are transplants rejected?
- Direct and indirect recognition of alloantigens: -
- If the organ contains alloantigens (antigens present in only some individuals of a particular species, that stimulate the production of antibodies in those that lack this antigen), the recipient will produce antibodies that will attack the body's antigens (bc they haven't been taught not to recognise self-antigen)
- -----------
- Direct: the foreign cell thinks the host's antigen are pathogenic (bc it's taught the donor's antigen) --> puts peptide on surface causing immune response
- Indirect is opposite
- Difference b/w direct and indirect is the origin of the antigen
228
Describe Type 1 hypersensitivity diseases
- IgE-mediated hypersensitivity
- Allergen induces cross-linking of IgE bound to mast cells and basophils w release of vasoactive mediators
- Typical manifestations include systematic anaphylaxis and localised anaphylaxis (e.g. hay fever, asthma, hives, food allergies and eczema)
229
What is an immune-priviledged site? What are 2 examples?
- Zone of no immune response (immune cells can't enter)
| - Eyes, testicles
230
Sequence of events in immediate (Type I) hypersensitivity
1. First exposure to allergen
2. Antigen activation of TH2 cells and stimulation of IgE class switching in B cells
3. Production of IgE
4. Binding of IgE to specialised FC (grabbers) on mast cells
5. Repeat exposure to allergen
6. Activation of mast cell: release of mediators (degranulation --> allergic reaction)
------------
1st time exposed to allergen, won't notice // 2nd time, allergen directly binds to mast cell ---> reaction.
231
How do T cells become mature?
- Learn to not react to self (otherwise they die)
