Nervous System Flashcards
Functions of the nervous system:
- sensory receptors respond to stimuli
- CNS sums up the input it receives, stores memories, and creates motor responses.
- generates motor output
What does the central nervous system consist of?
brain and spinal cordd
What does the peripheral nervous system consist of?
nerves, which lie outside of the CNS
Three types of neurons:
sensory neurons, interneurons, motor neurons
Function of sensory neuron:
carries nerve signals from a sensory receptor to the CNS
Function of Interneuron and where it is found:
found in CNS and receives input from sensory neurons. sums up signals received from neurons and communicates with motor neurons.
Motor neuron function:
carries nerve impulses away from CNS to muscle fiber or organ or gland, which carries out the response.
Stimulus:
change that activates a neuron
Threshold:
minimum voltage that must be reached for action potential to occur. MUST BE MET TO START ACTION POTENTIAL.
Depolarization:
when an action potential begins, sodium gates open and Na+ rushes into cell. this causes the inside of axon to become positive.
Repolarization:
Na+ gate close and K+ channels open. K+ flows out of cell then the inside of axon becomes negative again. Then, sodium potassium pump completes the action potential. K+ goes back in the cell and resting potential is restored.
Sodium potassium pump:
pumps Na+ out and K+ into the neuron. (form of active transport and requires ATP)
Saltatory conduction:
in myelinated fibers, action potentials only occur at the nodes of ranvier.
Refractory period:
period of time immediately after an action potential during which the axon is unable to conduct another action potential. This ensures the one-way direction of the signal from the cell body down the length of the axon.
Synapse:
region of close proximity between two neurons
What do the synaptic vessels contain?
neurotransmitters
events at a synapse:
- nerve signals travel along an axon and reach an axon terminal.
- calcium ions enter the terminal and stimulate synaptic vesicles to merge with the sending membrane.
- neurotransmitter is released into the synaptic cleft and diffuses across to the receiving membrane.
Excitation=
sodium gates to open
inhibition+
potassium ions to exit the receiving neuron
CNS is wrapped in membranes known as:
meninges
Cerebrospinal fluid:
found between the meninges, cushions and protects the CNS. Also in the brain and central canal of spinal cord. drains into cardiovascular system.
Gray matter contains:
cell bodies and short, nonmyelinated axons.
White matter contains:
myelinated axons that run together in bundles called tracts. myelination occurs and white matter develops as child grows.
Structure and contents of the spinal cord:
central canal, gray matter and white matter. spinal nerves project from the cord and through small openings called intervertebral foramina.
What kind of disks separate the vertebrae in the spinal cord?
fibrocartilage intervertebral disks.
Dorsal root:
sensory fibers entering the gray matter
Ventral root:
motor fibers exiting the gray matter
Spinal cord functions:
a gateway for pain signals. motor signals from the brain pass down the spinal cord to the muscles. the center of reflex arcs.
Paraplegia:
damage in the thoracic region of the spinal cord, lower body and legs are paralyzed.
Quadriplegia:
if damage is in the neck region, all four limbs are affected.
Reflec arc sets:
- sensory neurons enter the cord and stimulate many interneurons.
- nerve signals then travel in these motor fibers to an effector
What is the brain made up of?
Cerebrum, diencephalon, cerebellum and brain stem.
Frontal lobe helps with:
movement, intelligence, behavior, memory.
Temporal lobe helps with:
speech, behavior, hearing, vision.
Parietal lobe helps with:
language, sensation, reading.
Occipital lobe:
vision
Cerebellum helps with:
balance, coordination
Brain stem helps with:
breathing, blood pressure, heartbeat, swallowing, consciousness. all the involuntary things.
Parts of the brain stem:
midbrain, pons, medulla oblongata.
Cerebral cortex is found on:
cerebrum
Diencephalon consists of:
Hypothalamus and thalmus
what does the hypothalamus do?
regulates hunger, sleep, thirst, body temp, water, balance.
What does the thalamus do?
two masses of gray matter which receives all the sensory input except smell. relays to area of cerebrum.
Longitudinal fissure:
deep groove that divides the left and right cerebral hemispheres.
Thick fold of the cerebrum:
gyri
Shallow grooves that separate the gyri:
sulci
Which neuron parts receive signals from sensory receptors of other neurons?
dendrites
the neuroglia cells that form myelin sheaths in the CNS are called:
Obligodendrocytes
repolrization of an axon during an action potential is produced by:
outward diffusion of K+
This part of the brain forms the link between the nervous system and the endocrine system:
hypothalamus
