Week 1 midterm 2 Flashcards
What is the CNS composed of?
the brain and spinal cord
What is the CNS primarily composed of and what are the 5 types?
glial cells
- astrocyte
- ependymal cells
- microglia
- oligodendrocytes
- schwann cells
What 4 things protect the CNS?
- glial cells
- bone
- connective tissue
- cerebrospinal fluid
What are the 2 functions of ependymal cells?
- creates barriers between compartments
- acts as a source of neural stem cells
What is the function of astrocytes? (astro = star)
CNS glial cells that develop neural connections and possibly modulate synaptic activity; remove neurotransmitter from synaptic cleft, communicate to neurons through chemical messengers, maintain normal electrolyte composition of ISF in CNS, protect neurons against toxic substances and oxidative stress, protecting against neural degeneration
What do microglia do?
glial cells that serve as phagocytes, cleaning and removing bacteria and dead cells, as well as protecting CNS from oxidative stress by removing reactive oxygen species
- scavengers
cranium
bony skull that encases the brain
vertebrae
a spinal cord that runs through a canal surrounded by bony vertebrae
Meninges
3 membranes that lie between the bones and tissues of the CNS
What are the 3 meninges?
- dura mater (hard mother)
- arachnoid mater (spider mother)
- pia mater (tender mother)
Dura mater
thick, outermost layer of the meninges that protects the brain and spinal cord, directly against the cranium
Arachnoid mater
middle layer thats a network shaped like a spider
Pia mater
innermost layer, delicate, directly against the brain
Cerebrospinal fluid
Protects the CNS by acting like a cushion and maintains a stable ISF environment
- clear watery and salty
Where is cerebrospinal fluid secreted into and where does it flow?
into the ventricles and flows through the subarachnoid space
What forms the lateral ventricles?
the first and second ventricles
Where does the cerebral aqueduct lead?
from the third ventricle in the diencephalon to the fourth ventricle in the brainstem
Where is the third ventricle located?
in the diencephalon
Where is the fourth ventricle located?
in the brainstem
What do villi do?
the fingerlike projections of the arachnoid membrane at which cerebrospinal fluid is reabsorbed into the blood
What does the chorioid plexus do?
circulates the cerebrospinal fluid to subarachnoid space and ventricles
- picks what substrate it transports
What indicates infection?
When the CSF contains protein and/or blood cells (they ain’t supposed to be there)
Concentration of K+ is _____ in the CSF
lower
concentration of H+ is ______ than in plasma
higher
Concentration of Na+ is _______ to that in blood
similar/higher
What is the total volume of CSF in around a 150lb animal
125-150mL
How much CSF does the choroid plexus produce per day and how often is it recycled?
400-500mL/day, recycled 3 times per day
CSF depends on what for energy?
Blood flow
What does the brain rely on for energy?
glucose, oxygen and in extreme cases, ketones (obtained through the metabolism of fatty acids/lipids)
What are capillaries?
sites of exchange between blood and interstitial fluid
What is lactate?
the usable form of glucose that the CNS (brain) uses for energy
What is the blood-brain barrier?
special anatomy of the CNS capillaries that limits exchange (selective - keeps unwanted things from the blood from crossing over into ECF of the CNS)
What are capillaries composed of? (x2)
endothelial cells and pores