Hubs progress test 2 Flashcards
1
Q
what is a group of cell bodies in the nucleus called in the CNS?
A
nucleus
2
Q
What is a bundle of axons called in the CNS
A
tract
3
Q
What is a group of cells bodies in the cerebral cortex or the spinal cord called in the CNS
A
grey matter
4
Q
what is a bundle of axons in the cerebral cortex or spinal cord called in the CNS
A
white matter
5
Q
what is a group of cell bodies called in the PNS ?
A
Ganglion
6
Q
What is a bundle of axons called in the PNS?
A
Nerve
7
Q
What is the function of an astrocyte (CNS glia)
A
supplies nutrients to neurons, ensheath blood capillaries and injury response.
8
Q
What is the function of microglia (CNS glia)
A
They are the immune cells of the CNS and they engulf microorganisms and debris.
9
Q
What is the function of ependymal (CNS glia)
A
Line filled fluid spaces of the brain and spinal fluid, these have cillia to circulate the cerebral spinal fluid
10
Q
What is the function of the oligodendroctyes (CNS glia)
A
They support nerve fibres and ensheath them with myelin.
11
Q
What are the gaps between the myelin sheath called and what is their purpose?
A
Nodes of ranvier, these increase the conduction velocity.
12
Q
what are the factors of the somatic efferent division?
A
It is vountary movement.
There are two neurons between the brain and effector ( upper motor neuron and the lower motor neuron)
The axons of the neurons are mylenated
The neurotransmitter is acetylcholine and the effector is skeletal muscle.
13
Q
What are the two divisions of the autonomic efferent nervous system and what neurotransmitter do they use?
A
Sympathetic (fight or flight) uses norepinephrine, parasympathetic (rest and digest) uses acetylcholine.
14
Q
Briefly describe the steps of an action potential
A
- The cell membrane is depolarised to threshold (-60mV)
- Rapid depolarisation of the cell due to the massive entry of Na+
- Repolarisation due to the exit of K+ out of the cell
- Hyperpolarisation due to the excess of K+ ( as the vg K channels are slower to open and close than sodium)
- Return to resting membrane potential (-70mv)
15
Q
What are the three type of Ion channels and how are they gated?
A
Chemical gated ion channels opened by the presence of a neurotransmitter
Voltage gated ion channels is opened by the presence of a voltage change
Mechanically gated ion channels are opened by a change in shape (eg squash or stretch)
16
Q
What is the movement of ions when the ion channels are open?
A
Both flow passively. Na+ into the cell. K+ out of the cell
17
Q
What is a local potential?
A
A change in the membrane potential voltage at a localised area (dendrites or cell bodies), this occurs by a neurotransmitter binding and opening the chemically gated ion channels.
18
Q
Excitatory Local potential vs Inhibitory local potential
A
Excitatory= causes depolarisation
a pre synaptic neuron releases an excitatory neurostransmitter which opens the chemically gated Na+ ion channels, this causes Na+ to enter the cell causing the post synaptic cell. this causes depolarisation (membrane more +ve)
Inhibitory= causes hyperpolarisation
a pre synaptic neuron releases an inhibitory neurostransmitter which opens the chemically gated K+ ion channels, this causes K+ to exit the cell causing the post synaptic cell. this causes hyperpolarisation (membrane more -ve)
19
Q
Spatial summation vs temporal summation
A
spatial= summed input from mutliple pre synaptic nerves
temporal= summed input from the repeated firing of one pre synaptic nerve
20
Q
How do lipid soluble hormones work
A
they are released from the endocrine gland cells, they require a carrier protein to take them through the bloodstream.
As they are lipid soluble they are able to diffuse across a cells plasma membrane and bind to intracellular receptors in the cell.
This stimulates the creation of new proteins or enzymes to produce a response.
21
Q
what are hormones released from and what are they made out of
A
released from endocrine gland cells (look like an egg) and they are made from amino acids and proteins
22
Q
what happens to a used or excess hormone
A
broken down or recycled, excreted through sweat urine or poo.
23
Q
what are the 6 charactaristics of lipid soluble hormones
A
- Thyroid hormones and steriods (eg cortisol)
- thyroid hormones are premade and stored, whereas cortisol is made as needed.
- Require a carrier protein to be transported in the blood stream
- Can diffuse across the plasma membrane, bind to a receptor in the cytosol or the nucleus
- They stimulate gene transcription to make new proteins (DNA interaction building new protiens)
- These have a slower respose and last hours to days
24
Q
What are the 6 characteristics of water soluble hormones
A
- Catecholamines, peptides and proteins
- They are all premade and stored
- Do not require a carrier protein
- They bind to plasma membrane receptors
- This activates the G protein which activates the 2nd messengers.
- This is a fast process as the 2nd messengers are already made eg heart rate, breathing rate. Adrenaline
25
What is the filum terminale?
A piece of fiberous non neural tissue that anchors the spinal cord.
26
What is the conus medularis?
a piece of non neural tissue at the end of the spinal cord
27
Where does the spinal cord finish?
at the 1st of the lumbar vertebrae
28
What are the regions of spinal nerves and how many are at each of them?
cervical- 8 pairs
thoracic- 12 pairs
lumbar- 5 pairs
sacral- 5 pairs
coccygeal- 1 pair
29
What is the large collection of spinal nerves at the bottom of the spinal cord called?
the cauda equina
30
What information is at the dorsal part of the spinal cord
Dorsal = posterior.
The sensory afferent information (from PNS into CNS)
31
What information is at the ventral part of the spinal cord
Ventral= anterior
The motor (efferent = exit) information (from the CNS out to the PNS)
32
What are 3 features of the dural folds?
1) They form the inner layer of the dura mater
2) Seperate the major divisions of the brain
3) Provide stability of the brain within the cranium
33
What is the name and location of the three dural folds?
1) Falx cerebri- seperates the cerebral hemispheres
2) Falx cerebelli- seperates the cerebellar hemispheres
3) Tentorium cerebelli- seperates the cerebrum from the cerebellum
34
What are the three features of the Venous sinus?
1) located where two layers of dura mater seperate
2) collecting veins
3) collect 2 things- venous ( deoxygenated) blood from the brain, and old cerebrospinal fluid that has circulated through the ventricular system
35
What are the 4 features of the arachnoid layer?
1) it is the middle layer below the dura and above the pia mater.
2) It doesnt extend into the sulcus
3) contains two special features - subarachnoid space and the arachnoid granulations
4) contains blood vessels within the subarachnoid space.
36
Feature of the subarachnoid space
It is filled with cerebrospinal fluid and contains blood vessels
37
Feature of the arachnoid granulations
To transport old cerebral spinal fluid from the subarachnoid space to the venous sinus
38
What are the 4 features of the Pia Mater
1) the inner layer of the meninges
2) it is transparent and delicate
3) The blood vessels in the arachnoid sit ontop of the pia mater
4) This layer adheres to the brian following the gyri and going down into the sulcus
39
What are the 4 features of the ventricular system?
1) a network of interconnected spaced (ventricles) in the brain
2) these are filled with cerebral spinal fluid which nourishes and protects the brain
3) the spaces are lines with ependymal cells which circulate the cerebral spinal fluid
4) the cerebral spinal fluid is produced in the choriod plexus
40
Name the ventricles in decending order
lateral horne (one in each hemisphere)
third ventricle (in the diencephalon)
cerebral aqueduct (in the midbrain)
fourth ventricle (the level of the cerebellum)
central canal (spinal cord)
41
What is the circulation path of the cerebrospinal fluid
lateral ventricle, third ventricle, cerebral aqauduct, 4th ventricle, subarachnoid space where it travels around the brain and spinal cord, finishing at the arachnoid granulations into venous sinus.
42
what are the 4 features of the cerebral spinal fluid
1) produced in the choroid plxus within the ventricles
2) surrounds the cns in the subarachnoid space
3) provides support and cushion
4) transports nutrients and waste
43
where are the parathyroid glands located and what hormone do they release?
4x of them sitting posterior of the thyroid gland
they secrete parathyroid hormone which is the most important hormone for ca2+ homeostasis
44
what hormone do the kindeys release?
calitriol
45
what hormone does the thyroid gland release?
T3 and T4
46
what do the kidneys do when the body has hypercalcemia
They absorb less Ca2+ from the pre urine, as well as they covert less vitamin d into calcitriol which means less ca2+ is taken from food.
47
What occurs to excess glucose?
It is stored in the liver and skeletal muscle in the form of glycogen.
It is stored in adipose fat as fat.
48
What hormones does the pancrease secrete and from what cells?
Has islet cells.
Alpha cells release glycagon
Beta cells release insulin
49
what occurs in the body to correct hypoglycemia? (fasting state)
the alpha islet cells in the pancrease release glucagon
this causes the liver to
gluconeogenesis- building new glucose to release into the blood
glycogenolysis- the breakdown of glycogen to release more into the blood
Ketone synthesis-building ketones to release into the blood (an alternative form of energy- fat)
50
what occurs in the body to correct hyperglycemia (fed state) ?
beta islet cells in the pancrease detect levels and release insulin.
All cells in the body have insulin receptors therefore all body cells have an increased glucose intake from the blood.
Liver and skeletal muscle cells take excess glucose from the blood to store as glycogen and adipose fat for glycogen storage.
51
name the three sulcus and what they divide and the fissue in the brain
central suclus- seperates the frontal lobe with the parietal lobe
lateral sulcus- seperates the temporal lobe from the frontal and parietal lobe
parietal-occipital suclcus- seprates the parietal from the occipital part of the brain
transverse fissure- seperates the cerebrum from the cerebellum
52
what is the definiton of sensory transduction?
Converting a sensory stimulus into an action potential
53
What four types of information does neuron activity contain?
1) modality- the type of stimulus detected by a specific type of receptor
2) duration- the time period action potentials fire
3) intensity- the rate that action potentials fire
4) location- where the receptors are in the body
54
what are the 4 types of sesnsory receptors
thermoreceptor
chemoreceptor
mechanoreceptor
noiceceptor
55
what are the three subtypes of mechanoreceptors and what are their functions
tactile- skin touch
proprioreceptor- proprioception (limbs in relation to the torso/ trunk)
baroreceptor- pressure (blood vessels, airways etc)
56
tonic vs phasic receptors
tonic are slow adapting- eg noiceceptors. these are continually active and the action potential frequency changes when the stimulus intensity changes
phasic are fast adapting- eg thermoreceptors. these are normally silent and when a change occurs they send an action potential but they stop quickly.
57
large receptive field vs small receptive field
large= less sensitive and less accurate localisation (eg legs, arms, torso) less representation on the somatosensory cortex map
Small= more sensitive and more accurate localisation
58
how many sensory neurons per receptive field are there?
one
59
what connects the posterior of the pituitary gland to the hypothalamus?
Neurons, their cell bodies lie in the hypothalamus with their axons being in the gland
60
what are the two posterior pituitary gland hormones and what are their functions?
oxytocin- water solube, stimulates milk release for breastfeeding as well as uterine contraction for childbirth
Anti-diuretic hormone- water soluble, the kidney is told to reabsorb water when dehydrated (stress and exercise response)
61
how is the anterior pituitary gland connected to the hypothalamus?
By a portal bloodstream- the hypothalamis neurons secrete releasing or inhibitng hormones, these travel via the blood portal and bind to receptors in the anterior pituitary glands causing it to release anterior pituitary hormone.
62
what are the three anterior pituitary gland hormones called?
growth hormone- stimulates the liver, skeletal muscle and adipose fat for mobilisation
thyroid stimulating hormone- water soluble and stimulates the thyroid gland to release thyroid hormone (increases basal metabolic rate)
Adrenocorticotropin hormone- stimulates the adrenal galnd for the release of cortisol in a daily pattern and for stress response
63
what events cause the thyroid hormone to be released
1) stimulus is exercise or cold stress
2) the hypothalamus secretes - thyroptropin releasing hormone
3) causes the anterior pituitary gland to secrete thyroid stimulating hormon
4) this causes the thyroid gland to secret thyroid hormones (t3 and t4) throughout the whole day.
5) all body cells can take thyroid hormones which increases basal metabolic rate.
Note! the release of T3 and T4 hormone has a negative feedback loop to anterior and hypothalamus so they secrete less of their hormones.
63
When is the highest growth hormone levels during the day and during an individuals lifetime?
Fluctuates during the day- highest at night
children higher than adults- peak during puberty and decline with age
63
what are the direct effects of growth hormone?
fuel mobilisation
muscles- stop cells taking in glucose and stimulate protein synthesis
liver- stimulates glucose synthesis from stored glycogen
adipose- increased fat breakdown
64
how does initiating movement occur in voluntary movement?
primary motor cortex (made of cell bodies of the upper motor neurons)- these are the neurons involved in directing voluntary movement
64
how does planning movement occur in voluntary movement?
prefrontal cortex- neurons involved in decisions to move
premotor cortex- neurons involved in organising movement sequences to achieve the outcome
65
How does modifiying movement occur in voluntary movement?
the basal nuclei- posture and automatic movements, muscle tone, refines movements
cerebellum- stores and facilitates learning, planning and execution of motor programmes
66
what does a small motor unit do?
has a motor neuron and activates few muscle fibres- these are for more precise movements
67
what does a large motor unit do
a motor unit and it activates lots of muscle fibres- for forceful movements
68
what is the process of a stretch reflex
1) stretch receptors are stretched
2) mechanically gates na+ receptors open in dendrites of sensory neuron
3) entry Na+ depolarises= an action potential along sensory axon to spinal cord
5) synapse between sensory axon= depolarises the motor neuron cell body
6) action potential along the motor axon to NMJ
7) causes muscle to contract= reflex
69
what are the elements of a withdrawel reflex
noiceceptors are activated
a sensory neuron depolarises= ap to spinal cord
sensory neurons stimulate interneurons
= an excitation of motor neurons this stimulates flexors
inhibition of motor neurons stimulating extensors
= withdrawal of the effected limb
70
What is an additional role of a sensory neuron in a stretch reflex response
sensory neuron stimulates inhibitory interneuron= prevents activation of motor neuron that activates the hamstrings = no opposition knee extension
71
what are the main differences between voluntary and reflex movement
voluntary- initialed by brain neurons, time delay varies (~100ms).
reflex- rapid reproducable automatic movement. no brain neurons, single neuron circuit in peripheral and spinal. consistent timing (~40ms)
72
what is the region that houses the thalamus and hypothalamus called?
diencephalon
73
what are the four cerebral lobes and their fuctions
Frontal lobe- motor language and personality
Parietal lobe- somatosensory and primary somatosensory cortex
Occipital lobe- vision
Temporal lobe- memory and hearing
74
what axon tract cross from side to side and an example
Commisural- eg corpus callosum
75
What axon tracts go between cerebral cortex and other regions of the CNS and an example
projection- corticospinal tract
76
what axon tracts go between brain areas on the same side?
association
77
what are the two key pathways
corticospinal tract and the dorsal column pathway
78
features of the cortical spinal tract
a voluntary movement (efferent)
starts at the primary motor cortex
and ends at the perpiphery eg effector muscle
79
features of the dorsal column pathway
somatosensory pathway (afferent)= specifically fine touch
starts at periphery
ends at primary somatosensory cortex
80
what occurs when there is damage to the motor cortex?
muscle weakness+ paralysis in the region of the body that corresponeds to the location of the motor cortex. On the opposite side
81
what occurs when there is damage to the somatosensory cortex
the ascending info has nowhere to go= a lack in pereception of tough in the region of the body that corresponds to the location on the somatosensory cortex.
On the opposite side
82
what happens at damage at the spinal cord?
the damage occurs on the same side
83
describe the dorsal column pathway in terms of the neurons involved and where they are located
afferent system
neuron one: cell body in dorsal root ganglion (this is a unipolar axon) its input zone is the peripheral fibre that is from the sensory receptor in the skin and its central fibre is the output zoner ascending up towards the brain.
Neuron 2- cell body in the medulla oblongata
the axon crosses to the opposite side and ascends
Neuron 3- cell body in the thalamus
its axons ascend into the somatosensory cortex where is synapses on the cell body of the somatosensory cortex neuron= the perception of touch .
84
describe the corticospinal pathway and the neurons involved
efferent (exciting) system
upper motor neuron= cell body in primary motor cortex. axon extends to the spinal cord on the opposite side
lower motor neuron= cell body in ventral horn (grey matter) of spinal cord.
The axon extends out of the spinal cord into the body where it makes a synapse on skeletal muscle
85
where is the primary motor cortex located in the brain?
In the pre central gyri
86
where is the primary somatosensory cortex located in the brain?
in the post central gyri
87
what are the sequence of events resulting in non stress cortisol being released
stimulus- day night rhythm, low blood glucose
hypothalamus- corticotriopin releasing hormone
anterior pituitary gland- adrenocorticotropin hormone
adrenal gland- cortisol from adrenal cortex
results= liver,muscle and fat mobilising their fuel
pancreas opposing insulin, stimuluating glucagon
cardiovascular maintainign stable blood pressure
decreased inflammation increasing the immune system
88
what parts of the adrenal glands secrete different hormones
cortex= cortisol & aldosterone
medulla= catecholamines ( adrenaline and noradrenaline)
89
what events occur for adrenaline to be secreted?
the sympathetic nerves stimulate catacholamine release (adrenaline) from the medulla of the adrenal gland
90
what are the effects of adrenaline being released
increases oxygen uptake and delivery of blood to cells (increased breathing rate, heart rate increased, blood pressure increase vasoconstriction)
Increases fuel mobilisation (liver glycogenolysis, glucogenesis, muscles glucogenesis and fat lipolysis)
91
what are the 3 stages of the stress response and what is the main event occuring at each of them?
1- Alarm phase- adrenaline main hormone fight or flight response
2: resistance phase- alarm phase depleated glycogen stores so lipid and protein stores are moblised. cortisol dominant hormone
3: exhaustion phase- lipid reserved depleated organs are damaged and strutural proteins are broken down. results in organ failure
92
What are the two cortisol disorders and what are their symptoms
Addisons disease (hyposecretion) - reduced cortisol and aldosterone= loss of appetite, fatigue and low blood pressure
Cushings disease (hypersecretion)- excess cortisol = thin arms and legs with weight held in torso- stretch marks and easily bruised and moon face
93
What are the three growth hormone disorders and what are their symptoms
Dwarfism (hyposecretion)- not enough growth hormone= short
Gigantiusm (hypersecretion)- excess growth hormone before epiphesial plates fused = tall
Acromegaly (hypersecretion)- excess growth hormone after epipheseal plates have fused= enlarged features, eg jaw and hands
94
What are the four thyroid hormone disorders and what are their symptoms
Infantyle hypothyroidism- not enough thyroid hormone, poorly developed thyroid, not enough iodine in mums diet= delayed growth and development, low metabolic rate
Adult hypothyroidism: removed thyroid gland, not enough iodine in diet= low metabolic rate, weight gain, sensitivity to cold
Simple Goitire (hyposecretion)- not enough TH released so no negative feedback to TRH and TSH. Thyroid stimulating hormone keeps secreting which swells the thyroid gland.
Graves Disease (hypertsecretion) too much thyroid hormone- high metabolic rate, weight loss, bulging eyes, increased heart rate
95
what are the two calcium disorders and what are their sympotoms
Hyperparathyroidism- tumor cause too much parathyroid hormone= soft and deformed bones, kidney stones
Hypoparathyroidism- damaged parathyroid glands reduced plasma Ca+= muscle freeze/ spasms/cramps, seizures
96
what are the two glucose disorders and their symptoms
type 1 diabetes hyposecretion of insulin- damaged beta cells by virus or autoimmune. cannot secrete insulin therefore high plasma glucose= excessive urine and extreme thirst. require insulin injections
Type 2 diabetes- unhealthy lifestyle (diet, exercise etc)
Hyposensitivity- the insulin receptors on the cells become resistant to insulin due to high levels
Hyposecretion- as insulin resistance worsens the beta cells wear out, reduced insulin = excessive urine and extreme thirst.
97
What are the microbes of the immune system (smallest to largest)
viruses
bacteria
fungi
protozoa
98
Function and elements of the primary lymphatic system
production of white blood cells (lympohocytes)
thymus- school for t cells, learn not to react to self
bone marrow- source of stem cells develop into innate and immune adaptive responses
99
function and elements of the secondary lyphatic system
sites where immune responses are initiated
spleen- site of initiation response against blood born pathogens
lymph nodes- located on lyphatic vessels wherer lymph fluid from blood and tissue is filtered- site of initiaion for immune response
100
physical and chemical features of the skin surface
physical:
dendritic cells - increasing surface area to interact with other immune cells
epidermis and dermis
chemical
antimicrobial peptides form in microbial cell membranes
lysosomes- breaks down bacterial cell walls
sebum has a low ph inhibiting microbial growth
salt is hypertonic produced by sebum
101
physical and chemical features of the mucous membrane s
line hollow tracts of the body
mucus layer- cillia lined, beat to move mucus from the respiratory tract up to clear bacteria and dust
epithelium- tightly packed live cells constantly renewed (contains mucus goblet cells)
chemical defense
stomach= low ph
gall bladder= bile
intensine= digestive enzymes
mucus and defensins
lysozyme (tears and urine )
102
Innate immunity features
surface barries - skin and mucus membranes
internal defenses- phagocytes, natural killer cells, inflammation and fever
already in place
fast response
fixed
limited- cant identify certain species
no specific memory
103
adaptuve immunity features
humeral immunity- b cells
cellular immunity- t cells
improves during the response
slow response
adaptive
highly specific- can tell differenced between the cells
long term specific memory
104
what neurotransmitters are released in the PNS autonomic system (sympathetic and parasympathetic)
sympathetic- 2nd neuron= acetylcholine
3rd neuron= noradrenaline
parasympathetic 2nd and 3rd neuron= both acetylcholine
105
what neurotransmitters are released in the PNS for the somatic divison?
only acetylcholine
106
what are the effectors of the autonomic division?
smooth and cardiac muscle and glands
107
where are the locations of synapses in the autonomic division? (sympathetic and parasympathetic)
sympatheic- 1st in the brain or spinal cord, 2nd very close to CNS in ganglia
parasympathetic; 1st in brain or spinal cord
2nd very close to the target
108
what is a refractory period?
limits how many action potentials occur per second and prevent action potentials from moving backwards
109
what is the absolute refractory period
begins when the voltage gated Na+ channels open while theyre activated, until they close
110
what is the relative refractory period
when the voltage gated Na+ channels begin closing
111
what ions are moving during the absolute refractory period
the stimulus causes Na+ channels to open causing the Na+ to rush into the cell= depolarisation.
when Na+ channels inactivate K+ channels activate causing to K+ to leave the cell (repolarising )
112
what ions are moving during the relative refractory period
The volatage gates K+ channels begin to close and the Na+ begin to reactivate. Causing hyperpolarisation
All the Na+ channels close bringing back to resting membrane potential.
113
how does a myelin sheath increase conduction velocity
the myelin wrapping decreases the Na+ leakage, more Na+ in the axon means there is more diffusion. there is Na+ in excess so when it diffuses it is still in high enough concentration to bring membrane to threshold.
114
Chemical defenses of the skin
antimicrobial peptides- defensins
lysosomes breaking down bacterial cell walls
sebum has a low ph
produced salt which is hypertonic
The epithelium layer of the skin has tightly packed live cells that are a good physical barrier
115
what are the three layers of the skin?
epidermis- dead cells phagocytic
dendritic cell- immune cells, increase surface area to interact with other immune cells, important for getting an immune response
dermis- thick layer of connective tissue- phagocytic immune
116
Can a 2nd action potential be generated in the absolute and relative refractory period?
Absolute no
Refractory a second action potential can be generated, only if the stimulus is larger than normal
117
Neuron to neuron transmission
Tiny synapses- one of thousands per cell
requires summation- rarely bring to threshold
inputs can be excitatory or inhibitory
variety of neurotransmitters used
118
Neuron to Muscle transmission
Large synapses, each muscle only has input from one neuron.
No summation required- brings to threshold by itself
inputs are only excitatory
only acetylcholine used.
119
where are the cell bodies of automatic neurons?
in the lateral horn
120
where does efferent information travel out of the spinal cord?
through the ventral root ganglion.
121
Direct effects of growth hormone
fuel mobilisation
muscle-inhibits cellular uptake of glucose
liver- stimulates glucose synthesis
adipose- increases fat breakdown
122
Indirect effects of growth hormone
insulin like growth factor
this is released from liver cells when stimulated by growth hormone
promotes the growth of bones, muscle and other tissue
