Module 5 (1/2) Flashcards
(85 cards)
1
Q
What are receptors? (2)
A
- Detects stimulus and passes to CNS
(1) - Specific receptors for specific stimuli
(1)
2
Q
What specific receptors are there? (4)
A
- Chemoreceptors detect chemicals
(1) - Thermoreceptors detect heat (1)
- Mechanoreceptors detect pressure
(1) - Photoreceptors detect light (1)
3
Q
What is the Pacinian corpuscles? (3)
A
- Type of mechanoreceptor (1)
- Found deep in skin (1)
- Action potential caused by stretch
mediated sodium ion channel
opening by pressure (1)
4
Q
What are the 3 types of neurons? (3)
A
- Sensory neurons (1)
- Relay neurons (1)
- Motor neurons (1)
5
Q
What do all types of neurons have in common? (5)
A
- Cell body containing nucleus (1)
- Dendrites (1)
- Twig like projections that receives
information from neurons (1)
- Twig like projections that receives
- Axon (1)
- Tube like structure that carries
impulse away from cell body (1)
- Tube like structure that carries
6
Q
What is a sensory neuron + structure? (2)
A
- Carries action potential from
receptor to CNS (1) - Cell body in the middle and one
long dendron (1)
7
Q
What is a relay neuron + structure? (2)
A
- Carries action potential between
sensory and motor neurons (1) - Contains the most dendrites (1)
8
Q
What is a motor neuron + structure? (2)
A
- Carries action potential from CNS to
an effector (1) - Less dendrites than relay and one
long axon (1)
9
Q
What is resting potential? (2)
A
- When there is a charge difference
between the inside and outside of
the membrane (1) - Known as being polarised which is
-70mV (1)
10
Q
How is resting potential maintained? (2)
A
- Sodium potassium ion pumps
actively pumps 3Na+ out for every
2K+ in (1) - Ensures there is a charge difference
with the outside of membrane being
more positive (1)
11
Q
How does an action potential occur? (3)
A
- Sodium ion channel opens and ions
flood into the membrane by
facilitated diffusion (1) - Membrane is depolarised to -55mV
where an action potential occurs (1) - Potential difference across a
membrane decreases until +30mV
(1)
12
Q
What is meant by threshold potential? (2)
A
- At -55mV ‘All or nothing’ response
is reached (1) - Where any depolarisation above
this number results in an action
potential (1)
13
Q
What happens once potential difference reaches +30mV? (3)
A
- Sodium ion channels close and
Potassium ion channels open (1) - Potassium ions move out the
neuron down their electrochemical
gradient (1) - Repolarisation occurs as there is a
charge potential re established (1)
14
Q
What is hyperpolarisation? (3)
A
- Charge difference exceeds resting
potential of -70mV (1) - Too many potassium ions exit the
neuron as the ion channel is slow to
close (1) - The sodium-potassium ion pump
returns the neuron to -70mV (1)
15
Q
What is refractory period? (3)
A
- A brief point after the action
potential where another action
potential can’t occur (1) - Since the ion channels are
recovering and cannot be made to
open (1) - Ensures action potential don’t
overlap and go one direction
(1)
16
Q
How does saltatory conduction occur? (3)
A
- Myelin sheath made up of Schwann
cells act as electrical insulator on
axon (1) - Impulse jumps from nodes of
Ranvier (1) - Reduces distance action potential
needs to travel and increases
transmission speed (1)
17
Q
What is a synapse? (2)
A
- Gap between neurons (1)
- Passes action potential by releasing
neurotransmitters rather than
electrical impulse (1)
18
Q
What’s the structure of synapses? (4)
A
- Neurone before synapse is
presynaptic neurone (1) - Neurone after synapse is
postsynaptic neuron (1) - Space in between these neurones is
synaptic cleft (1) - The end of the presynaptic neurone
is the synaptic knob (1)
19
Q
Explain synaptic transmission? (6)
A
- Action potential reaches synaptic
knob and and triggers opening of
voltage gated calcium ion channels
(1) - Calcium ions move into synaptic
knob and trigger vesicles containing
neurotransmitters to move to the
presynaptic membrane (1) - Vesicle fuses with presynaptic
membrane and contents are
released by exocytosis (1) - Neurotransmitters diffuse across
synaptic cleft and bind to specific
receptors on postsynaptic
membrane (1) - These receptors trigger the opening
of sodium ion channels which
causes depolarization and an action
potential beyond -55mV (1) - The neurotransmitter is removed
from synaptic cleft and is
reabsorbed by the presynaptic
neuron and recycled, preventing
continuous stimulation of an action
potential (1)
20
Q
What is synaptic divergence? (2)
A
- Multiple neurones connecting to
one neurone (1) - Action potentials from multiple
neurones become amplified and
produces a stronger impulse (1)
21
Q
How is a bigger stimulus produced? (2)
A
- Action potential is always the same
voltage with depolarisation till
+30mV (1) - The bigger the stimulus the more
frequent an action potential will
occur along a neurone (1)
22
Q
What is spatial summation? (2)
A
- When lots of presynaptic neurones
converge on a single postsynaptic
neurone (1) - All release small amounts of
neurotransmitters enough to
stimulate an impulse (1)
23
Q
What is Temporal summation? (2)
A
- When one presynaptic neurone fires
action potentials at quick
successions (1) - Repeatedly releasing
neurotransmitters into the synaptic
cleft (1)
24
Q
What is the difference between the endocrine system and nervous system? (4)
A
Endocrine system is:
- Slower to bring about an effect (1)
- Longer lasting (1)
- Can act on multiple target tissues (1)
- Use of chemicals rather than
impulses (1)
25
How do hormones travel? (1)
- Travel around the bloodstream (1)
26
What are secondary messengers + example? (2)
- Will activate reactions inside target
cells where hormones can't get
inside (1)
- E.g. cAMP that activates a cascade
for the breakdown of glycogen (1)
27
What is the structure + location of the adrenal glands? (2)
- Adrenal cortex on the outside and
adrenal medulla in the inside (1)
- Found on top of the kidneys (1)
28
What's the function of the adrenal medulla? (2)
- Secretes hormones catecholamines
(1)
- Includes adrenaline and
noradrenaline to increase energy
levels (1)
29
What's the function of the adrenal cortex? (2)
- Secretes steroid hormones (1)
- Cortisol for metabolism regulation (1)
- Aldosterone controls blood pressure (1)
30
What are islet of Langerhans and its structure? (3)
- Endocrine part of the pancreas
surrounded by capillaries (1)
- Made up of alpha cells that secretes
glucagon into the bloodstream (1)
- Made up of beta cells that secretes
insulin into the bloodstream (1)
31
How do plants increase their survival chances? (3)
- Alkaloids and Tannins taste bitter
and interfere with digestion (1)
- Alarm pheromones stimulate other
plants to produce toxins such as
tannins (1)
- Folding upon touch (1)
32
What is the effect of Phototropism and why? (4)
- Shoots have positive phototropism
and move towards the sun (1)
- For maximum photosynthesis (1)
- Roots have negative phototropism
and move away from the sun (1)
- They move deeper in the soil for
more water (1)
33
What is the effect of Geotropism and why? (3)
- Shoots have negative Geotropism
(1)
- Roots have positive Geotropism (1)
- Same reason as phototropism (1)
34
What are the 5 groups of plant hormones? (5)
- Auxins (1)
- Gibberellins (1)
- Abscisic acid (1)
- Cytokinin (1)
- Ethene (1)
35
What is Indoleacetic acid (IAA)? (3)
- Type of auxin (1)
- Diffuses into shaded region to cause
elongation (1)
- Therefore allows plants to undergo
phototropism/geotropism (1)
36
How do you investigate for phototropism? (2)
- Cover plants at different points with
aluminum foil (1)
- Have lamp at fixed distance for 48
hours and keep temperature
constant (1)
37
How do you investigate for geotropism + example? (2)
- Petri dishes filled with crest seeds and
moist cotton wool at different angles
in dark cupboard (1)
- Root grown towards gravity and shoot
away from gravity (1)
38
What is apical dominance? (3)
- Auxins promote the growth of apical buds
and inhibits the side roots from the lateral
buds (1)
- Less energy used so more for plant growth (1)
- Maximises sunlight exposure for photosynthesis
(1)
39
What happens when the apical bud is removed? (2)
- Auxin levels drop (1)
- Side shoots continue to grow (1)
40
How do you investigate apical dominance? (2)
- Cut off shoot tips and replace with paste containing
and not containing auxin (1)
- Count the number of side shoots on each plant (1)
41
What are gibberellins? (3)
- Plant hormones that stimulates seed germination (1)
- By stimulating the breakdown of starch into glucose
for respiration in the seed (1)
- Works with auxins synergistically or antagonistically during cell
elongation (1)
42
What is the function of abscisic acid? (3)
- Prevents seed germination by inhibiting gibberellins (1)
- Inhibits elongation in roots (1)
- Controls stomatal closure (1)
43
How do you investigate gibberellins? (2)
- Water 2 groups of plants with water containing or not containing
gibberellins (1)
- Measure the mean stem height after 30 days (1)
44
What happens when a leaf ages? (3)
- Auxin levels reduce and ethene levels rise (1)
- Abscission layer develops until ethene causes its cell wall to break
(1)
- Leaf separates from plant and falls off (1)
45
How do stomates close? (3)
- Abscisic acid binds to receptors on guard cell
membrane and opens calcium ion channels (1)
- Influx causes potassium ion channel to open
as ions exit the cell and cause water potential to
increase inside the cell (1)
- Water diffuses out, causing the guard cell to become
flaccid, closing the stomata (1)
46
What is negative feedback mechanism? (2)
- Mechanisms that act to reverse change in the body (1)
- E.G. As temperature increases negative feedback mechanism will ensure
changes occur to decrease temperature (1)
47
What is positive feedback mechanism? (2)
- Mechanisms that amplify change by accelerating biological pathway (1)
- E.G. Platelets release chemicals to produce more platelets (1)
48
Why isn't positive feedback involved in homeostasis? (1)
- Doesn't keep internal environments within a normal range (1)
49
How is body temperature detected? (3)
- Thermoreceptors detect change (1)
- Signal sent to hypothalamus (1)
- Signal sent to effector (1)
50
How do hormones increase body temperature? (1)
- Adrenaline is released to increase amount of respiration (1)
51
What happens when blood glucose is too high? (4)
- Pancreas detects change and stimulate beta cells in islets of Langerhans to
secrete insulin (1)
- Binds to insulin receptors in liver and muscle cells (1)
- Increases permeability of membranes to glucose (1)
- Stimulates glycogenesis and increases rate of respiration (1)
52
What happens when blood glucose is too low? (4)
- Pancreas detects change and stimulate alpha cells in islets of Langerhans to
secrete glucagon (1)
- Binds to glucagon receptors in liver cells (1)
- Triggers gluconeogenesis (1)
- Stimulates glycogenolysis and decreases rate of respiration (1)
53
What is glycogenesis, gluconeogenesis and glycogenolysis? (3)
Glycogenesis = Conversion of glucose to glycogen (1)
Glycogenolysis = Breakdown of glycogen into glucose (1)
Gluconeogenesis = Production of glucose from non-carbohydrates such as
lipids and proteins (1)
54
What's the difference between type 1 and 2 diabetes effects? (2)
- Type 1 means immune cells kills beta cells to stop insulin to be produced (1)
- Type 2 means body cells stop responding to insulin properly as insulin
receptors stop working (1)
55
What are endotherms and ectotherms? (4)
Ectotherm = Animals that rely on behavioral adaptations to control internal temperature (1)
- Reptiles and Amphibians (1)
Endotherm = Animals that rely on physiological adaptations to control internal temperature (1)
- Mammals and birds (1)
56
What's a transducer + example? (2)
- Converts one form of energy into another (1)
- E.G. Receptors (1)
57
What's meant by excretion? (1)
- The removal of metabolic waste products from the body (1)
58
What are the functions of the liver? (4)
- Breaks down amino acids into urea (1)
- Detoxifies the blood (1)
- Stores glycogen (1)
- Makes bile to aid lipid digestion (1)
59
What is the ornithine cycle? (2)
- Converts excess amino acids into urea (1)
- As they can't be stored and cause damage to tissues (1)
60
What are the steps of the ornithine cycle? (4)
- Amino acids are deaminated to form ammonia and organic acids (1)
- Organic acids are respired or stored as glycogen (1)
- Ammonia is toxic and combines with CO2 to form urea (1)
- Urea is released in the bloodstream where it is filtered by the
kidneys and excreted in urine (1)
61
What are the liver vessels? (8)
- Hepatic artery (1)
- Transports oxygenated blood to the liver (1)
- Hepatic vein (1)
- Transports deoxygenated blood out the liver (1)
- Hepatic portal vein (1)
- Connects the digestive system to and liver (1)
- Bile duct (1)
- Transports bile to the gall bladder to be stored (1)
62
What is the liver made up of? (2)
- Cylindrical liver lobules (1)
- Made up of liver cells knowns as hepatocytes (1)
63
What is a sinusoid? (1)
- Capillary that connects the hepatic vein and hepatic portal vein to
the central vein (1)
64
What happens when blood passes through sinusoids? (3)
- Hepatocytes converts toxic substances into less harmful substances
(1)
- Kupffer cells attached to sinusoid walls remove bacteria from
bloodstream (1)
- Kupffer cells also break down old red blood cells (1)
65
What is the structure of kidneys? (3)
- Inside and outside of kidneys are renal medulla and renal cortex (1)
- Renal artery and vein transports blood in and out (1)
- Individual structures that filter blood are called nephrons (1)
66
What are the functions of kidneys? (2)
- Removes excess water, ions and urea from blood as urine (1)
- This involves: (1)
- Ultrafiltration
- Selective reabsorption
67
What is the structure of ultrafiltration? (2)
- Bowmans capsule (1)
- Surrounding ball of capillaries called the glomerulus (1)
68
How does the glomerulus have high hydrostatic pressure? (2)
- Efferent arteriole is smaller in diameter than afferent arteriole (1)
- More blood being transported into glomerulus results in high
pressure (1)
69
How does ultrafiltration occur? (3)
- High hydrostatic pressure forces small molecules (glucose
and salt) to be pushed from the blood to bowman's capsule (1)
- Filtered through basement membrane, capillary endothelium and
epithelium of the bowman's capsule (1)
- Enters the proximal convoluted tube (1)
70
What structures are found at the kidney cortex? (4)
- Bowmans capsule (1)
- Proximal convoluted tube (1)
- Distal convoluted tube (1)
- Top half of collecting duct (1)
71
What structures are found at the kidney medulla? (2)
- Loop of Henle (1)
- Lower half of the collecting duct (1)
72
What is the function of the proximal convoluted tube? (2)
- Glucose is reabsorbed by active transport and facilitated diffusion
(1)
- PCTs endothelium has microvilli to increase S.A (1)
73
How is water reabsorbed during selective reabsorption? (3)
Through osmosis in:
- Distal convoluted tube (1)
- Descending limb (1)
- Collecting duct (1)
- From lower water potential by ascending limb (1)
74
How is urine disposed? (1)
- Transported from collecting duct to bladder through ureter (1)
75
What is the loop of Henle made up of? (2)
- Descending limb (1)
THEN TO THE:
- Ascending limb (1)
76
Whats the function of the descending limb? (3)
- Permeable to water but impermeable to ions (1)
- Water moved out of the nephron by osmosis (1)
- Lower medulla water potential set up by ascending limb sodium
ions pump (1)
77
How do organisms in dry conditions adapt their kidneys? (3)
- Extra-long loop of Henle (1)
- More sodium ions pumped into the kidney medulla (1)
- More water moved out the nephron by osmosis (1)
78
Whats the function of the ascending limb? (3)
- Permeable to ions but impermeable to water (1)
- Top of ascending limb has sodium ions pumped by active transport
(1)
- Bottom of ascending limb having more concentrated filtrate from
osmosis means sodium ions enters the medulla by facilitated
diffusion (1)
79
What is Antidiuretic Hormone (ADH)? (3)
- Controls water content in urine (1)
- Increasing permeability of collecting duct and DCT (1)
- Example of negative feedback (1)
80
What happens when blood water potential decreases? (4)
- Osmoreceptors in hypothalamus detect this change (1)
- Hypothalamus signals posterior pituitary gland to secrete ADH (1)
- Increased permeability in DCT and collecting duct increases water
potential in bloodstream (1)
- A small, more concentrated urine is produced (1)
81
What is kidney failure? (3)
- When kidneys stop filtering toxic substances out the blood (1)
- Caused by infection or high blood pressure (1)
- Viewed from low glomerular filtration rate (1)
82
What problems are caused by kidney failure? (3)
- Ion imbalance results in brittle bones (1)
- Excess blood urea results in vomiting and weight loss (1)
- Accumulation of fluids lead to swelling (1)
83
How is kidney failure treated? (6)
Dialysis (1)
- Blood content (Ions, Water, Urea) diffuse into dialysis fluid to reach
normal concentrations (1)
- Expensive, diet required and regular hospital visits (1)
Kidney transplant (1)
- Cheaper in long term with better quality of life (1)
- Surgery risks and immunosuppressant drugs suppresses immune
system for other diseases (1)
84
How do pregnancy tests work? (1)
- Monoclonal antibodies connected to beads bind to hormone hCG
(1)
85
How are drugs tested? (2)
- Urine samples on test strips with it's complimentary hormone (1)
- Further test of gas chromatography (1)
