Unit 4: Week 1 Flashcards
What is the nervous system and its function?
A network of neurons that carry signals around the body (to and from the spinal cord and brain) working closely with the endocrine system to maintain homeostasis.
It’s responsible for perception, behaviour, voluntary/involuntary movement.
What are the two devisions of the nervous system and what are the made up of?
Central NS- processes, interprets, stores informations, and coordinates responses. Made up of the brain and spinal cord. + glial cells
Peripheral NS- transmits information to the CNS from receptors in the periphery and to the periphery from the CNS. Made up of 12 pairs cranial nerves, 31 pairs spinal nerves, ganglia and enteric plexus of the gut +glial cells
That divisions can the PNS be broken down into and what are they responsible for?
ANS- controls smooth muscle of BV/, cardiac muscle/visceral organs, ducts and it regulates involuntary processes.
SNS- controls skeletal muscle which facilitate voluntary movement
What is a neuron and what are the called in the CNS vs PNS?
A neruron is the functional unit of the NS. It is a specialised electrically excitable cell that transmits nerve impulses.
CNS- Cell body: neuclus
Axon: tracts
PNS- Cell body: ganglion
Axon: nerve
What are the cells that make up the myelin sheaths called in the CNS vs PNS?
CNS: oligalenrocytes
PNS: Schwan cells
What are the types of neurons in the NS?
Sensory neuron
Motor neuron
Interneuron
What is the structure and function of sensory neurons?
They have a single dendrite, axon and cell body attached by process. They are unipolar
They are also called affront neurons and they carry information towards the CNS from a receptor
sensory neuron
-nerve cell convert stimuli to electrical signals
-Short axon single dendrite
- Cell body on the center of axon attached by processes
-efferent pathway
-unipolar-one dendrite
- Can be mylinated
- cell body outside CNS
-10 mil neurons (more than motor)
They have cell bodies in the dorsal root ganglion
What is the structure and function of a motor neuron?
They have short dendrites, long axon and are multipolar.
They carry nerve impulses away from the CNS to effector targets
All somatic motor neurons are myelinated
Cell bodies in the spinal cord
5mill motor neurons (less than sensory)
What is the structure and function of an interneuron?
They typically have short axons. Typically unmylinated. Multiple interneuron can synapse with a sensory neruron to coordinate responses.
Why are some cells myelinated and others not?
Myelination takes time and energy and not all signals need to be sent quickly. Some neves have ganglion to relay signals. Some axons are short (interneuron) and somtimes a large number of neurons need to fit into a small area (interneuron in spinal cord- Grey matter (lipids in myelin is missing)
What is the structure and function of the cerebrum?
Split into two hemispheres with a fissure running down the middle
Preforms all higher functions.
What is the structure and function of the cerebellum?
Underneath cerebrum and adjacent to the brains stem.
It coordinates movement, balance and posture.
What is the structure and function of the brain stem?
Continuous with the spinal cord.
Acts a relay and coordinates automatic functions.
MO- RR HR BP some reflexes
Pons- regulation or respiration
MB- pain suppression and controls fight or flight
What are fluid filled cavities in the brain called and what are their functions?
They are called ventricles and an area inside them called the charotid plexus makes CSF which provides cushioning and shock absorbtion as well as a metabolic function nutrients and waste
What are the holes in the skull and spine that the nerves exit from called? What kind of nerves exit them?
Foramina
Cranial- 2 sensory and the rest are mixed
Spinal- mixed
