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Physiology Flashcards

(90 cards)

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1
Q

Cell body

A

Contain nucleus and cell organelles. May have more than one nerve fibre extending from it.

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2
Q

Dendrons

A

Conduct impulses towards the cell body. Are small and break up into small terminals at the ends.

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3
Q

Axons

A

Conduct impulses away from the cell body, are thinner than dendrites and may be several metres long.

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4
Q

Schwann cells

A

Insulate axon making up myelin sheath

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5
Q

Node of ranvier

A

Sections of axons not insulated

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6
Q

Synaptic knobs

A

At ends of axons and allow communication w/ other neurones or effectors via neurotransmitter.

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7
Q

Simple reflex

A

Rapid response to stimulus

Automatic/involuntary

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8
Q

Receptor

A

Detects stimulus and transmits impulses along sensory neurone to spinal cord.

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9
Q

Endrocrine system

A

Involves release of hormones from endocrine glands, which travel through the bloodstream to target cells affecting their physiological activities and regulating metabolic pathways.

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10
Q

Peptide hormones mechanism

A

Are polar and cannot pass the cell membrane, so interact w/ specific receptors, producing a second messenger that activates or inhibits specific enzyme activities, regulating metabolic pathways.

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11
Q

Steroid hormones mechanism

A

Pass through cell membrane and interact w/ receptor sites on transcription factors, increase/decrease rate of gene expression.

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12
Q

How does hormonal control differs to nervous control?

A

1) Chemical only
2) Transmission via circulatory system
3) Pathway none specific, cells are specific
4) Slow transmission, slow acting
5) Long term changes
6) Widespread

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13
Q

How does nervous control differ to hormonal control?

A

1) Chemical and electrical
2) Transmission via nerve impulses and chemicals
3) Pathway specific due to nerve cells
4) Rapid transmission and response
5) Short term change
6) Localised response

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14
Q

Autonomic nervous system

A

Part of the peripheral nervous system which controls activites inside the body which are normally involuntary

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15
Q

What controls the autonomic nervous system?

A

Medulla and hypothalamus

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16
Q

Sympathetic nervous system area of influence

A

Effects diffuse

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17
Q

Parasympathetic nervous system area of influence

A

Effects localised

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18
Q

Sympathetic nervous system transmitter

A

Noradrenaline

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19
Q

Sympathetic nervous system conditions

A

Danger, stress and activity, controls stress reactions

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20
Q

Sympathetic nervous system general effects

A

Increased metabolic rate
Increased blood glucose
Increased rhythmic activities
Raised sensory awareness

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21
Q

Parasympathetic nervous system transmitter

A

Acetylcholine

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22
Q

Parasympathetic nervous system conditions

A

Rest, controls routine body activities

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23
Q

Parasympathetic nervous system general effects

A

Decrease blood glucose
Decreases rhythmic activity
Restores awareness to normal levels

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24
Q

Saltatory conduction

A

Impulse transmission is faster as they jump from one node of ranvier to the next

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25
Refractory period
Seperate discrete impulses determining maximum frequency along neurone.
26
Cholinergic neurones
Neurones possessing the neurotransmitter acetylcholine
27
Adrenergic neurones
Neurones possessing the neurotransmitter noradrenaline
28
EPSP
Excitatory postsynaptic potentials
29
Summation
Addictive effects of several EPSP's causing depolarization of the post synaptic membrane
30
Spatial summation
Two or more impulses arrive in different places at the same time on the same neurone.
31
Temporal summation
Impulses arrive at the same place on the axon within a short time period.
32
IPSP
Inhibitory post-synaptic potential, hyperpolarisation of the axon membrane.
33
Inhibitory synapses
Membrane permeability to Cl- and K+ is higher, they diffuse out/in the axon according to their conc. gradient and cause IPSP's making action potentials harder to generate.
34
Sclera
External eye covering made of collagen. Protects and maintains shape of eye.
35
Cornea
Transparent front part of sclera, is curved and refracts light towards the retina.
36
Choroid
Rich in blood vessels supplying the retina, contains melanin which prevents reflection of light in the eye.
37
Ciliary muscles
Muscles in the ciliary body which alter the lens shape.
38
Ciliary body
Junction of sclera and cornea contains blood vessels and ciliary muscles.
39
Suspensory ligaments
Attaches lens to ciliary body
40
Lens
Transparent, elastic, biconvex structure, provides fine adjustment for focusing light on the retina.
41
Iris
Muscular diaphragm containing pigment which gives eyes it's colour. Controls amount of light entering the eye via radial muscles.
42
Pupil
Hole in the iris where light enters
43
Retina
Contains photoreceptor cells, rods and cones and associated neurones
44
Fovea
Region of retina containing only cones enabling maximum discrimination of detail. Most light rays focused here.
45
Optic nerve
Bundle of nerve fibres carrying impulses from the retina to the brain
46
Blind spot
Point where the optic nerve leaves the eye. No photosensitive cells here.
47
Vitreous humour
Clear semi-solid substance maintaining the shape of the eyeball.
48
Aqueous humour
Clear salt solution secreted by the ciliary body.
49
Pupil constriction
Stimulated by the parasympathetic nervous system. Circular muscles contract, radial muscles relax, iris constricts.
50
Pupil dilation
Stimulated by the sympathetic nervous system. Radial muscles contract, circular muscles relax. Pupil dilates.
51
Eye accommodation for near vision
1) Light rays more diverging at the eye. 2) Cornea refracts light and ciliary muscles contract. 3) Suspensory ligaments slacken, lens goes convex 4) Image focused on retina due to higher convergence.
52
Eye accommodation for distant vision
1) Light rays less diverging at the eye 2) Cornea refracts light and ciliary muscles relax 3) Suspensory ligaments pulled taut, lens less convex 4) Image focused on retina due to lower convergence
53
Rod cells
Contains rhodopsin which breaks down into retinal and opsin when light falls on them. In strong light, pigment is broken down faster than it can be reformed, becoming bleached. In dim light breakdown is slower, production keeps up.
54
Cone cells
Contain iodopsin, and have a high threshold. Only high intensity light breaks down the pigment. Pigment is resynthesised faster than rhodopsin. Have a 1:1 relationship w/ a bipolar neurone giving high acuity.
55
Rod cell, visual sensitivity
Many rods to a single bipolar cell, and many of these to a neurone. More rods at the edges of the field of vision, highly sensitive.
56
Cerebellum
Hindbrain. Controls balance, precision and fine control of voluntary movements. Learns tasks requiring conscious thought. These tasks eventually become unconscious.
57
Medulla
Hindbrain. Controls a number of vital physiological processes. Contains cardiovascular and ventilation centres. Recieves input from different receptors via the hypothalamus. Impulses from the cerebral cortex can modify its activity. Has a role in reflexes like sneezing, coughing and salivation.
58
Hypothalamus
Midbrain. Able to coordinate and control the ANS. Receives sensory input from all receptors of the ANS. Covers emotional responses and body regulation sensations. Links nervous and endocrine system via pituitary gland. Controls anterior pituitary gland.
59
Muscle fibres
- Cylindrical in shape and enclosed by a sarcolemma - Are multinucleate - Contain numerous myofibrils w/ cross-striations - Are arranged parallel - Are surrounded by collagen and connective tissue which form a tendon
60
Tendon
Connects muscle to bone
61
What are the protein filaments present in muscle?
Thin filaments are actin | Thick filaments are myosin
62
Where is myosin present in muscle?
A-band | Outer regions are darker as they contain both actin and myosin
63
Why is the H zone at the centre of the A band lighter than the rest of the A band?
Only contains myosin filaments
64
What connects the myosin filaments in the A band?
M line
65
What protein filaments does the I band contain?
Actin filaments
66
What does the Z line connect?
All protein filaments
67
The characteristic repeating banding pattern in muscle is known as?
Sarcomere
68
What changes occur to the banding pattern during muscle contraction?
- H zone (in A band) narrows - Outer regions of A band widen - I band narrows - A band remains the same size
69
Structure of myosin
Made up of many myosin molecules, heads extend out over the surface. Heads have ATPase activity, hydrolysis of ATP provides energy for muscle contraction.
70
Structure of actin
Made up of actin monomers. | Is associated with troponin and tropomyosin
71
Sliding filament hypothesis
Actomyosin bridges form as myosin heads attaches to actin filaments. These break and reform and reform along the actin filament pulling them past the myosin filaments. ATP provides energy for formation and breakdown of the bridges.
72
Tropomyosin's role in muscle contraction
Covers the binding site on the actin filament, so switches on/off the mechanism. Is attached to troponin.
73
Troponin's role in muscle contraction
When Ca2+ bind to it, it moves tropomyosin, uncovering the actin binding site, allowing actomyosin cross bridges to form.
74
Calcium ions role in muscle contraction
Bind to troponin, causing tropomyosin to move and allowing actomyosin cross bridges to form. Actively moved back into sarcoplasmic reticulum when muscle is no longer stimulated. Stimulate ATPase, hydrolyzing ATP for breakdown of bridges.
75
Sequence of events at neuromuscular junction
1) Action potential arrives at synapse, triggering events of synaptic transmission to sarcolemma. 2) Attachment of acetylcholine to receptors on sarcolemma cause EPP's 3) This triggers Ca2+ in the muscle fibre triggering muscle contraction 4) Cholinesterase breaks down acetylcholine 5) Acetylcholine is resynthesized using ATP
76
EPP
End plate potential, released upon entry of Na+ intro the postsynaptic knob of the neuromuscular junction.
77
Myofibril
Protein strand which makes up skeletal muscle. Linked by cross striations.
78
Where does translocation occur?
Phloem
79
Translocation
Transport of photosynthetic products in the plant to: - Respiring non photosynthetic cells - Growing areas - Storage areas
80
Cells making up the phloem
Sieve elements - plates and tubes | Companion cells
81
Companion cells
Cells lying adjacent to sieve elements possessing many mitochondria and dense cytoplasm.
82
How does thick waxy cuticle help prevent water loss of xerophytes?
Provides a longer diffusion pathway, reducing the rate of evaporation.
83
How do hairs of leaf surfaces of xerophytes help reduce water loss?
Trap a layer of air, which becomes saturated with water vapour, reducing the water potential gradient for water loss.
84
How do epidermal pits in xerophytes help prevent water loss?
Beneath leaf surface, contain stomata, trap layer of air which becomes saturated with water vapour, reducing water potential gradient for evaporation.
85
Bergman's rule
Total heat production of endotherms depends on body volume, and heat lost depends on surface area.
86
Allen's rule
Species living in colder climates have smaller extremities.
87
Adaptations of kangaroo rat
``` Nocturnal Relies on respiration and food for water Very long loops of henle High ADH level in blood Water condenses in nasal passages during exhalation. ```
88
How does a high ADH blood level reduce water loss?
Means more water is reabsorbed from distal convoluted tubules and collecting duct in kidneys
89
Migration
Periodic long distance movement, from one location to another.
90
Reasons a bird may migrate
Endogenous - e.g. hunger | Exogenous - e.g. photoperiod

Biosciences (24 decks)

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