Nervous System Flashcards
function of nervous system
control and communicate
components of the nervous system
brain, Spinal cord and peripheral nerves
how is the nervous system set up to detect signals?
subdivided into smaller systems by locations ( Central and Peripheral)
- wants to detect internal and external environments, evaluate information and initiate response
what is the CNS
structural and functional centre of entire nervous system
- brain and spinal cord
what is PNS composed of
nerves that lie in the outer region
- cranial nerves nad spinal nerves
Somatic vs autonomic?
somatic control skeletal muscles (voluntary)
autonomic control involuntary muscles
afferent vs efferent divisions?
afferent division is incoming messages (arriving) from the visceral receptors and efferent is outgoing (exiting)
the autonomic nervous system efferent pathways are further divided into?
Sympathetic division
and parasympathetic
sympathetic
prepares body for fight or flight
parasympathetic
normal resting activities
- rest and repair
the distension of the stomach caused by the presence of food trigger the _______ to _________
parasympathetic, to increase secretion of gastric juice
Neurons vs Glial cells?
neurons- excitable cells that conduct impulses
glial cells- do not conduct info but support the function of neurons
glial cells- how many types in the CNS, how many in PNS?
do not conduct information, but support the function of neurons
- there are 4 major types of glial in the CNS (astrocytes, microglia, ependymal, oligodendrocytes)
- Schwann cells in the PNS
within the neutron what does axon transport look like?
cell body can make neurotransmitters, motor molecules move proteins on the cytoskeleton highway for the release at the synaptic knobs
Astrocytes?
star shaped and the largest and most numerous type of glial
- connect to neurons and capillaries
- transfer nutrients from the blood to the neurons
- form tight sheaths around brain capillaries, which, with tight junctions between capillary endothelial cells, constitute the blood- brain barrier (BBB)
what is purpose of the BBB
protects the brain from harmful substances in the blood stream while also allowing for supply of nutrients to the brain
how does the BBB protect the brain?
it strictly limits transport into the brain through both tight junctions and metabolic ( enzymes) barriers and a double barrier
what do astrocytes do for the BBB?
webs of astrocytes form tight sheets around the brains capillaries, this allows for a double barrier around the capillaries–> astrocyte feet and endothelial cells
conscious movements are controlled by?
somatic nervous system
how does sympathetic influence the liver and digestion/reproductive organs?
will “turn them off”/ decrease this activity as there are other priorities
Sympathetic nervous system and the heart
SA node ( pacemaker of the cell) when it receives Sympathetic stimulus–> increase heart rate
what can cross the BBB?
liposomes ( vesicle with a membrane composed of a PPL bilayer)
gases, lipid soluble, glucose and other harmful things as well
benefit of liposomes passing through the BBB
deliver drugs or genetic material into the cell
Microglia are _______ of the brain
macrophages of the brain
-small, usually stationary cells
act as scavengers (modified immune cells)
what cannot diffuse the BBB?
water soluble, need specialized transporter
Ependymal cells
Ep-i-dime-al
- create barriers (protection) between compartments and are sources of neural stem cells
resemble epithelial cells and form thin sheets that line fluid-filled cavities ( cerebral-spinal fluid) in the CNS - some produce fluid others aid in circulation of fluid
Oligodendrocytes
- form myelin sheaths
are smaller than astrocytes
Multiple sclerosis is a disorder of _____
oligodendrocytes
- most common disease od the CNS
- myelin loss and destruction, exposed nerve fiber
- plaque like lesions form
- failure in nerve conduction
- communication is impaired