Nervous system 1 Flashcards
What is the central nerves system?
Brain and spinal cord
Wich division of the peripheral NS carries signals TO the CNS from sensory receptors?
Sensory (afferent)
Wich division of the PNS carries signals from the CNS?
What kind things do they signal?
Motor (efferant)
Muscles contract, glands secrete
What branch of the Motor division carries signals to skeletal muscles, that you have concious control over?
Somatic
What branch of the motor division do you have no concious control over?
Autonomic
The ______________division – sends signals that cause “fight or flight” responses in body organs and systems, i.e. increased heart rate, breathing rate, redirection of blood to muscles and away from the gut etc.
Sympathetic
The ____________division generally acts to restore the resting state, i.e. maintain the “status quo”, bringing activity levels back to “normal”.
Parasympathetic
How many types of cells are there in the nervous system and what are they called?
Neuroglia and neurons
What do neuroglia do? (4)
protect and support neurons segregate and insulate neurons secrete chemicals to guide young neurons to their proper connections. promote neuron health and growth.
What are the 4 types of neuroglia in the CNS?
- Astrocytes
- Microglia
- Ependymal cells
- Oligodendrocytes
Astrocytes
Astrocytes – most common, radiating processes attach to neurons and their endings,
cover capillaries in the brain and provide support to neurons.
They regulate the chemical environment around neurons by controlling exchange between
neurons and capillaries.
Microglia –
small cells that monitor the health of neurones and carry out a defense role within the CNS. (immune cells cannot normally enter the CNS).
Ependymal cells
epithelial like cells found within the central cavities of the brain and spinal cord that produce and circulate cerebrospinal fluid.
Oligodendrocytes
wrap around neuron fibers, forming insulating myelin sheaths in the CENTRAL ns
What are the 2 types of neuroglia of the PNS?
satelite cells and schwann cells
Schwann cells
surround nerve fibers, to form myelin sheath
What 4 things do all neuron cells have?
- Cell body
- Dendrites
- Axons
- Synaptic boutons
What are Dendrites?
– short, tapering, branching extensions of the cell which typically act as the receptive part of the cell.
- Part of neuron cells
What are axons?
long narrow tubes that extend out from the cell and “carry” the nerve signal from “A to B”.
What are Synaptic boutons?
swellings at the end of the axon that contain a chemical - NEUROTRANSMITTER, that is released when a signal arrives. The neurotransmitter acts on the target cell to switch it on or switch it off.
Since membranes present a significant barrier to charged solutes (ions) if they are crossing the membrane they must be doing so via special routes. These routes are a special group of membrane proteins called _____________.
CARRIER OR CHANNEL PROTEINS
If there is a concentration difference for an ion across a membrane because ions are charged there will be a charge difference too. Differences in charge are known as _____.
Voltage
voltages across the cell membrane, called _______ can affect___________.
membrane potentials
how ions move
if the inside of a cell is +ve and the outside -ve, what will happen?
–ve ions will want to enter and +ve ions will want to leave
if holes are opened in the membrane that allow ions to cross, then ions will move across the membrane in what direction?
Down CONCENTRATION GRADIENTS Along ELECTRICAL (CHARGE) GRADIENTS (voltages).
nerve and muscle cells at rest we see a small voltage across the cell membrane; what is this called?
the membrane potential (PDm).
So where does the PDm come from?
Where there is a difference in ion concentration across the cell membrane if a channel opens the ion will move out along its _________gradient.
what does this cause?
- Concentration
- The +ve ion takes charge from the inside to the outside so th inside becomes a bit -ve
What is the speed that a signal passes down a nerve dependent on? (2)
- the ________of the nerve fibre, ______ axons conduct faster than _____ones (up to a point).
- If the nerve is wrapped around by _______cells - ______Cells or _____________. This arrangement allows nerves to carry signals much faster by ______________
- the diameter of the nerve fibre, thicker axons conduct faster than thin ones (up to a point).
- If the nerve is wrapped around by glial cells - Schwann Cells or Oligodendrites. This arrangement allows nerves to carry signals much faster by SALTATORY CONDUCTION.
Whatis the fatty material around cells called?
Myelin
Myelin prevents the movement of ions across the membrane so ions can only cross the membrane at the _________
Nodes of Ranvier.
What is the fast myalenated system of signals called?
SALTATORY CONDUCTION.
What is at the end of the axon?
a Synapse
What are the 3 parts of the synapse?
The swelling at the end of the axon - synaptic bouton (bulb).
A space (synaptic gap) between the 2 cells.
c) The membrane of the receiving / target cell (post-synaptic membrane).
What is inside the synaptic bouton?
Neurotransmitter
On the target cell membrane (post-synaptic membrane) there are ______that grab hold of (bind to) the neurotransmitter. These receptors are typically _________________ that open or close to allow particular ions to cross.
RECEPTORS
LIGAND GATED CHANNELS
Whar neurotransmitters switch on their target cell called?
excitatory
What are neurotransmitters switch off their target cell
Inhibitory
What is the embryonic structure from wich the whole of the nervous system develops?
neural tube
What are the 3 main components of both cerebral hemispheres?
- Cortex
- White matter
- basal nuclei
What is white matter?
Myelinated nerve axons
What is basal nuclei>
Islands of grey matter
They have an important holistic role receiving input from the entire cerebral cortex as well as input from structures further down the neural tube.
What do commisural fibres do?
White matter that connects the 2 hemispheres
What do association fibres do?
White matter that connects diffrentareas of one hemisphere
What do projection fibres do>
white matter that connect the brain to the spinal cord
Name 4 things that basal ganglia does?
- Regulate cognition and attention
- start stop monitor the intensity of moovment
- inhibiting unnecessary moovments
- enabling multitasking
What does the deincephalon emcompas?
thalamus, hypothalamus and epithalamus
What happens at the thalamus?
Sensory nerve signals converge
relays information to appropriate part of the cortex
What is the name of the gland that secretes melatonin form the posterior of the epithalamus?
Pineal gland
________ the __________regulate the sleep-wake cycle and some aspects of mood
hypothalamus the epithalamus
Part of the _____________makes the cerebrospinal fluid that surrounds the brain and spinal cord.
epithalamus (choroid plexus)
What is the name of the stalk that goes from the hypothalmus to the patuitry gland?
infudibulum
Name 7 of the roles of the hypothalamus
- Autonomic control (controls the autonomic nervous system, BP, heartrate etc)
- Emotional response (the limbic system)
- Body tempreture regulation
- walter balance and thirst
- sleep-wake cycles
- control of the endocrine system
What are the 3 components of the brain stem?
Midbrain, pons, medulla oblongata
In the mid-brain the fluid component is called the ___________. Surrounding the aqueduct is a layer of grey matter – ___________, that has an important role in ____________
cerebral aqueduct.
periaqueductal grey,
pain Suppression
What is the name of the structure in the midbrain that coordinate head and eye moovments?
Superior and inferior colliculi
What is the substantia nigra inportant for?
Make dopamine to the basal ganglia
What area of the pons contrls breathing rhythm?
pneumotaxic centre
What happens at the medulla oblongata?
Motor nerves cross over
What 2 autonomic reflex centeres are there in the medulla oblingata?
- The cardio centre: (force and rate of heart contraction)
- Respiratory centre: rate and depth of breathing
Whhat connects with the pons and medulla?
The cerebellum
What does the cerebellum do?
Processes iput form the cerebal motor cortex and sensory
- has a body map, so toy know where body parts are in relation to eachother
What does the limbic system do?
FEELINGS D: (emotional, affective)
What does the reticular formation do?
Keep you awake
The spinal cord Extends from the base of the _______to the _________ at the base of the spinal column.
medulla to the corda equinae
The spinal cord has ___matter at its centre surrounded by __matter. Sensory nerves enter the grey matter from the ____side and motor nerves exit _______.
White
Grey
Dorsal
ventrally
Where do spinal nerves exit the spinal column?
between the pairs of vertebra
