Hubs progress test 2 Flashcards
what is a group of cell bodies in the nucleus called in the CNS?
nucleus
What is a bundle of axons called in the CNS
tract
What is a group of cells bodies in the cerebral cortex or the spinal cord called in the CNS
grey matter
what is a bundle of axons in the cerebral cortex or spinal cord called in the CNS
white matter
what is a group of cell bodies called in the PNS ?
Ganglion
What is a bundle of axons called in the PNS?
Nerve
What is the function of an astrocyte (CNS glia)
supplies nutrients to neurons, ensheath blood capillaries and injury response.
What is the function of microglia (CNS glia)
They are the immune cells of the CNS and they engulf microorganisms and debris.
What is the function of ependymal (CNS glia)
Line filled fluid spaces of the brain and spinal fluid, these have cillia to circulate the cerebral spinal fluid
What is the function of the oligodendroctyes (CNS glia)
They support nerve fibres and ensheath them with myelin.
What are the gaps between the myelin sheath called and what is their purpose?
Nodes of ranvier, these increase the conduction velocity.
what are the factors of the somatic efferent division?
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.
What are the two divisions of the autonomic efferent nervous system and what neurotransmitter do they use?
Sympathetic (fight or flight) uses norepinephrine, parasympathetic (rest and digest) uses acetylcholine.
Briefly describe the steps of an action potential
- 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)
What are the three type of Ion channels and how are they gated?
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)
What is the movement of ions when the ion channels are open?
Both flow passively. Na+ into the cell. K+ out of the cell
What is a local potential?
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.
Excitatory Local potential vs Inhibitory local potential
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)
Spatial summation vs temporal summation
spatial= summed input from mutliple pre synaptic nerves
temporal= summed input from the repeated firing of one pre synaptic nerve
How do lipid soluble hormones work
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.
what are hormones released from and what are they made out of
released from endocrine gland cells (look like an egg) and they are made from amino acids and proteins
what happens to a used or excess hormone
broken down or recycled, excreted through sweat urine or poo.
what are the 6 charactaristics of lipid soluble hormones
- 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
What are the 6 characteristics of water soluble hormones
- 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
What is the filum terminale?
A piece of fiberous non neural tissue that anchors the spinal cord.
What is the conus medularis?
a piece of non neural tissue at the end of the spinal cord
Where does the spinal cord finish?
at the 1st of the lumbar vertebrae
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
What is the large collection of spinal nerves at the bottom of the spinal cord called?
the cauda equina
What information is at the dorsal part of the spinal cord
Dorsal = posterior.
The sensory afferent information (from PNS into CNS)
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)
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
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
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
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.
Feature of the subarachnoid space
It is filled with cerebrospinal fluid and contains blood vessels
Feature of the arachnoid granulations
To transport old cerebral spinal fluid from the subarachnoid space to the venous sinus
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
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
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)
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.
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
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
what hormone do the kindeys release?
calitriol
what hormone does the thyroid gland release?
T3 and T4
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.
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.
What hormones does the pancrease secrete and from what cells?
Has islet cells.
Alpha cells release glycagon
Beta cells release insulin
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)
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.