7. Central Nervous System Flashcards
The four major regions of the brain:
- cerebral hemispheres
- diencephalon
- brain stem
- cerebellum
Cerebrum:
2 cerebral hemispheres of brain
most superior region, and largest
gyri
elevated ridges of tissue on surface of cerebrum
sulci
shallow grooves on surface of cerebrum
fissures
deep grooves separating large regions of the brain
longitudinal fissure
separates cerebral hemispheres
cerebral hemispheres are has 3 regions:
- cortex - superficial gray matter
- white matter - internal area, myelinated axons
- basal nucei - islands of gray matter deep within white matter, regulate movement
Cerebral cortex functions:
speech memory voluntary movement logical and emotional responses consciousness interpretation of sensation
Frontal lobe:
anterior segment of brain
control of skeletal muscles, language, memory
Parietal lobe:
posterior to frontal lobe
interprets sensory information - pain, temperature, touch
Occipital lobe:
posterior area of brain
visual interpretation
Temporal lobe:
inferior to frontal/parietal lobes
hearing and smell (olfactory)
Diencephalon includes:
thalamus
hypothalamus
limbic system
Brain stem includes:
mid brain
pons
medulla oblongata
reticular formation
Thalamus:
relays sensory information to cerebral cortex
relays motor information to the muscles
Hypothalamus:
integrates autonomic NS functions
regulation of body temperature, food intake, water balance, thirst.
links with endocrine system to help produce/release hormones
Cerebellum:
balance
fine motor control
learned motor function
Medulla oblongata:
controls heart rate, BP, breathing, swallowing
merges with spinal cord
Pons:
controls rate/depth of breathing, sleep/arousal
afferent and efferent fibre tracts
anterior to medulla oblongata
Midbrain:
controls visual pathways and eye movement
posterior aspect of brain stem
Brain stem:
combination of midbrain, pons and medulla oblongata
extension of spinal cord
Reticular formation:
diffuse mass of gray matter, extending length of brain stem
involves motor control of internal organs, digestive organ activity and RAS (reticular activating system)
Reticular activating system (RAS):
plays a role in conciousness, awake/sleep cycle
maintains cerebral cortex alertness
Name the 3 meningeal layers:
dura mater
arachnoid mater
pia mater
2 layers of dura mater:
periosteal and meningeal layers
3 protections for the CNS:
meninges
cerebrospinal fluid
blood-brain barrier
Subarachnoid space:
space between arachnoid mater and pia mater
filled with cerebrospinal fluid and blood vessels
Dura mater:
tough, double-layered membrane
composed of 2 fibrous connective tissue layers
Meninges 3 functions:
- cover and protect CNS
- protect blood vessels
- contain cerebrospinal fluid
Cerebrospinal fluid functions:
- reduce weight of brain by floating it - 1500g to 50g
- protects the brain from blows/injury
- removes waste from the CNS
- regulates chemicals and pH in CNS
Subdural space:
separates dura mater and arachnoid mater
Pia mater:
deepest layer of meninges
delicate connective tissue, clings tightly to brain
Blood-brain barrier function:
regulates which chemicals are allowed to interact with nerve cells of CNS
How does the blood-brain barrier protect neurons in the CNS?
forms a highly selective filter - least permeable capillaries in the body
only respiratory gases, fat soluble molecules and extremely small molecules can pass through from blood to neurons
regulates the type and amount of molecules
