Lesson 7 Flashcards
1
Q
Brain Stem
A
- Medulla oblongata
- Pons
- Midbrain
Reticular formation
2
Q
Medulla oblongata
A
- starts at the foramen magnum and goes to pons
- made up of sensory (ascending) tracts and motor (descending) tracts
- Contain Pyramids and ducussation of pyramids
3
Q
Medulla contains
A
- Pyramids and decussation of pyramids
- olive
- Gracile nucleus & cuneate nucleus
- Gustatory nucleus
- Cochlear nucleus
- Vestibular nucleus
4
Q
pyramids
A
- bulges of white matter on the anterior part of the medulla
- formed by the corticospinal tracts
5
Q
decussation of pyramids
A
- crossing of axons in pyramids
- 90% of axons cross here
- explains why each side of brain controls the opposite side of body
6
Q
Nuclei in the Medulla
A
- Cardiovascular center
- Medullary rhythmicity area of the respiratory center
- Vomiting center
- Deglutition center
7
Q
Cardiovascular center
A
- regulates the rate and force of the heartbeat & the diameter of blood vessels
8
Q
Medullary rhythmicity area of the respiratory center
A
- adjusts the basic rhythm of breathing (along with areas in the pons)
9
Q
Vomiting center
Deglutition center
A
- causes vomiting
- causes swallowing
10
Q
olive
A
- just lateral to each pyramid
- oval-shaped swelling
11
Q
inferior olivary nucleus
A
- within the olive
- receives input from:
cerebral cortex, red nucleus (midbrain),spinal cord - its neurons extend into cerebellum, where they regulate the activity of cerebellar neurons
- it provides instructions that the cerebellum uses to make adjustments to muscle activity as you learn new motor skills
12
Q
Gracile nucleus & cuneate nucleus
A
are associated with sensations of touch, pressure, vibration and conscious proprioception
13
Q
Gustatory nucleus
A
- from tongue to brain
- receives gustatory input from taste buds of tongue
14
Q
Cochlear nucleus
A
- part of the auditory pathway from inner ear to brain
- receives auditory input from cochlea of the inner ear
15
Q
Vestibular nucleus
A
- equilibrium pathway from inner ear to brain
16
Q
Injury to medulla
A
- by hard blow to back of head/upper neck
- can be fatal
- damage to medullary rhythmicity area is really bad
- alcohol overdose also suppresses the medullaryrhythmicity area and may result in death
17
Q
Pons
A
- consists of nuclei and tracts
- is a bridge that connects parts of the brain with each other
18
Q
Pons contains
A
- pontine nucleus
- pneumotaxic area
- apneustic area
19
Q
Pontine nucleus
A
- relays signals for voluntary movements from cerebral cortex to cerebellum
20
Q
Pneumotaxic area
A
Rhythm of breathing
21
Q
Apneustic area
A
Inhale/exhale
22
Q
Midbrain contains
A
- Cerebral peduncles
- Tectum
- Substantia nigra
- Red nuclei
23
Q
Cerebral peduncles
A
- paired bundles of axons
- axons from corticospinal tracts:
-motor area in cerebral
cortex to the SC - corticobulbar tracts:
-motor areas in cerebral
cortex to medulla - corticopontine tracts:
-motor areas in cerebral
cortex to pons
24
Q
tectum
A
-posterior part
-contains 4 rounded elevations:
superior colliculi
inferior colliculi
25
Q
superior colliculi
A
- nuclei in 2 superior elevations
- coordinates mvts of head, eyes, trunk in response to visual stim
26
Q
inferior colliculi
A
- nuclei in 2 inferior elevations
- coordinates mvts of head, eyes,
trunk in response to auditory stim
startle reflex- sudden mvts of head, eyes, trunk that occur when surprised by a loud noise
27
Q
Substantia nigra
A
- neurons release dopamine and help control subconscious muscle activities
- loss of these neurons is associated with Parkinson’sdisease
28
Q
Red nuclei
A
- involved in voluntary muscle movements
- rich blood supply
- iron-containing pigment
29
Q
Reticular formation
A
- is found throughout the brain stem
- it’s a net-like arrangement of grey and white matter
- grey matter – clusters of cell bodies
- white matter – small bundles of myelinated axons
30
Q
Reticular activating system
A
- within reticular formation
- consists of sensory axons that project to the cerebral cortex
- can be activated by visual stimuli:
- auditory stimuli
- mental activities
- pain, touch, pressure stimuli
- proprioceptive receptors
31
Q
RAS Involved in?
Active during?
A
- involved in consciousness
consciousness – state of wakefulness in which an individual is fully alert, aware and oriented
- active during arousal (awakening from sleep)
32
Q
Reticular activating system functions
A
- helps maintain attention and alertness
- prevents sensory overload by filtering out insignificant information so that it does not reach consciousness
- inactivation of the RAS produces sleep sleep – a state of partial consciousness from
which an individual can be aroused
33
Q
Damage to RAS
A
- damage to the RAS results in coma
- coma: a state of unconsciousness from which an individual cannot be aroused
- in the lightest stages of coma, people still have brain stem and spinal cord reflexes
- in deepest states, those reflexes are lost
- drugs such as melatonin affect RAS by helping to induce sleep
- anesthetics turn off consciousness via the RAS
34
Q
RAS motor axons do what?
A
- consists of motor axons that connect to the cerebellum and spinal cord to help regulate muscle tone
- muscle tone: the slight degree of involuntary contraction in normal resting skeletal muscles
- also involved in regulation of heart rate, BP, respiratory rate
- RAS does not receive input from olfaction so even strong odors won’t wake people up
