Exam 4 Flashcards
Efferent neurons
Takes information from the CNS
Afferent neurons
Takes information to the CNS
Spinal nerves
On each side of the vertebrae; “mixed” nerves of sensory and motor neurons
Cauda equina
Where the spinal cord goes from being compact to fraying off
Nerve
Bundle of neurons
Ganglion
Bundle of cell bodies outside the CNS
Dorsal root ganglion
The cell bodies of sensory neurons outside the CNS
Dorsal root
The axons of the sensory (afferent) neurons
Ventral root
Axons of motor (efferent) neurons
White matter
The region outside the spine; consists of the axons
Why is white matter white
Because it is myelinated
How are axons in white matter organized
- Short tract
2. Long tract
Short tract
Axons that connect parts of the spine
Long tract
Axons that connect the spine to the brain
Types of long tracts
- Ascending
2. Descending
Ascending long tracts
Carry information to the brain from the spine (sensory)
Descending long tracts
Carry information from the spine to the brain (motor)
Gray matter
The inside region of the spine; the cell bodies; the nissl bodies (ER) make it gray; this is the integration center; very organized/each section does something different
How do the cell bodies in gray matter accumulate
Based on function; organize into nuclei
Nucleus
Cell bodies organize themselves into different nuclei based on their function
Where is the amount of gray matter the greatest
- Cervical enlargement
2. Lumbar enlargement
Cervical enlargement
Area in the cervical area where there is more gray matter; controls movement of shoulder and upper limbs
Lumbar enlargement
Area in lumbar area where there is more gray matter; controls movement of lower limbs
Meninges
Protects the spine from the vertebrae in case of injury; the “air bags”
Dura mater
Meninge; The outermost membrane; “tough mother”
Epidural space
Space between dura mater and vertebrae that is filled with adipose tissue
Arachnoid mater
Meninge; The middle membrane
Pia mater
Meninge; The deepest membrane; wraps directly around the spine
Subarachnoid space
Space between arachnoid mater and pia mater; filled with cerebrospinal fluid (CSF)
Main function of the brain stem
Controls unconscious thought; visceral function/autonomic function
Medulla oblongata
Directly connected to the spinal cord; all sensory information goes through the medulla before going to the brain
How is the medulla oblongata separated
It is separated into different nuclei
Nuclei of the medulla
- Cardiovascular centers
- Respiratory rhythimicity centers
- Solitary nucleus
Cardiovascular centers
Controls heart function; autonomic
Parts in the cardiovascular centers
- Cardioacceleratory center
2. Cardioinhibitory center
Cardioacceleratory center
Enhances heart function; uses sympathetic neurons (fight or flight)
Cardioinhibitory center
Inhibits heart function; uses parasynthetic neurons (rest and digest)
How does the cardiovascular center know which center to use
- Baroreceptors
2. Chemoreceptors
Baroreceptors
Measure blood pressure and sends that information to the CNS
Chemoreceptors
Monitors the chemical content of blood
What chemicals in blood do chemoreceptors monitor
Oxygen and carbon dioxide
What does the medulla decide to do if chemoreceptors detect that carbon deoxide levels are too high
It uses sympathetic neurons to pump blood faster to get carbon dioxide out of the blood faster
Respiratory rhythmicity center
Controls respiration rate; stimulates muscles that make us inhale and relaxes them to exhale
Why are the respiratory rhythmicity center and cardiovascular centers right next to each other
Because they work together
What cant the respiratory rhythmicity center do
Decide when to inhale/exhale
What tells the respiratory rhythmicity center when to inhale/exhale
The pons
Solitary nucleus
Is a relay station; takes in sensory information from different places and makes sure that that information gets sent to the right centers; takes in information from visceral functions then sends it to the correct nuclei centers
Decussation
Means “crossing over”; where motor commands from one side of the brain cross over and go to the opposite side of the body (contralaterally
Pons
Controls muscle movements of the face
Respiratory center (of the pons)
A nuclei in pons
Parts in the respiratory center of the pons
- Apneustic center
2. Pneumotaxic center
Apneustic center
Responsible for causing respiratory muscles to contract/inhale
What does the apneustic center not know how to do
When to relax respiratory muscles in order to exhale
Pneumotaxic center
Silences the apneustic center in order to exhale/relax
What controls the respiratory centers in the medulla
The respiratory centers in the pons
Midbrain
Mesencephalon; the most conserved region, meaning most species have this
Corpora quadrigemina
Collection of 4 nuclei in the midbrain that control reflexes of the head and neck in response to stimuli
Superior colliculus
The top pair of corpora quadrigemina; controls reflex movements in response to visual stimuli
Inferior colliculus
The bottom pair of corpora quadrigemina; controls reflex movements in response to auditory stimuli
What is the natural purpose of the mesencephalon?
So that our reflexes protect us from predators
Red nucleus
Has a large blood supply; gives unconscious control of skeletal muscle; gives us resting muscle tone; sends out more commands then we need
Resting muscle tone
Even at rest, there is some tension generated in certain skeletal muscle; mainly for posture
Substantia nigra
Inhibits parts of the red nucleus from contracting the extra muscles that we don’t need to be contracted
Dopaminergic neurons
Neurons that extend from the substantia nigra to the red nucleus; secretes dopamine onto the red nucleus to inhibit it
Two types of receptors that bind to dopamine
- D-1 like receptors
2. D-2 like receptors
What kind of receptors does the red nucleus have?
D-2 like receptors
Parkinson’s
Dopaminergic neurons of the substantia nigra die so the red nucleus makes random muscle contractions
L-Dopa
Gets converted dopamine; used to treat Parkinson’s instead of Dopamine because of the blood-brain barrier
2 regions that the substantia nigra blocks
- Red nucleus
2. Cerebellum
Vermus
Tissue that runs down the middle of the cerebellum
The two lobes of the cerebellum
- Anterior
2. Posterior
What is in the cerebellum
Grey and white matter
Cerebellar cortex
The outer part; the grey matter
Purkinje cells
Neurons cells only found in the cerebellum; has a large system of dendrites
What is the difference between regular neurons and purkinje cells
Purkinje cells have a more extensive/larger system of dendrites
What kind of information do the purkinje cells take in
Information about proprioception
Proprioception
Knowing where you are in time and space
Proprioceptors
Send information to the cerebellum about where you are in time and space
What is the main function of the cerebellum
Controlling fine tuned movements that are learned
Peduncles of the cerebellum
- Superior cerebellar peduncle
- Middle cerebellar peduncle
- Inferior cerebellar peduncle
What is the function of the cerebellum peduncles
Carries motor commands out of the cerebellum
What does ethanol/alcohol do
It shuts down the cerebellum which inhibits fine motor proprioception movements
Ataxia
Loss of proprioception function
Parts of the diecephalon
- Epithalamus
- Thalamus
- Hypothalamus
Epithalamus
Top of diecephalon
Pineal gland
Within the epithalamus; secretes melatonin
Melatonin
Helps you go to sleep
Tryptophan
An amino acid that gets converted into sarotonin then the pineal gland turns it into melatonin
Thalamus
Middle of diecephalon; A relay station, meaning sensory information goes here and is then sent to the right place; also filters out the unimportant sensory information besides smell
Why isnt smell filtered by the thalamus
The neurons for smell dont run through the thalamus
Hypothalamus
Lowest on diecephalon; links the neural system and the endocrine system
Where is the pituitary gland located
In the sella turcica
What is the function of the pituitary gland
It secretes a lot of important hormones
What tells the pituitary gland when to or not to secrete hormones
Hypothalamus
Neuroendocrine
The hypothalamus is neuroendocrine; there are neurons that secrete molecules/hormones into the blood instead of into a synapse
Hormones that the hypothalamus releases
- Releasing hormones
2. Inhibiting hormones
Release hormones
Causes the pituitary gland to release hormones
Inhibiting hormones
Causes the pituitary gland to stop releasing hormones
Supraoptic nucleus
A nuclei of the hypothalamus; makes anti-diuretic hormone (ADH)
Anti-diuretic hormone
Helps you retain water
How does alcohol effect the supraoptic nucleus
It blocks the supraoptic nucleus from making ADH
Paraventricular nucleus
A nuclei of the hypothalamus; Makes oxytocin
Oxytocin
Important for bonding and induces smooth muscle contractions of the uterus during labor and delivery and of milk ducts during nursing
Pitocin
Man made oxytocin
What type of feedback loop is oxytocin
Positive feedback loop
Suprachiasmatic nucleus
A nuclei of the hypothalamus; controls the function of the pineal gland; controls when it secretes melatonin
What causes more secretion of melatonin
Light; visual sensory information
Preoptic area
A nuclei of the hypothalamus; controls body temperature by controlling blood flow
What does the preoptic area do if body temperature is too high
It dilates blood vessels that are superficial and near the skin and constricts blood vessels near the torso
What does the preoptic area do if body temperature is too low
It constricts blood vessels near the skin and dilates blood vessels near the torso
Cerebrum
Home to conscious thought; the main part of the brain
What surrounds the cerebrum
Pia mater, arachnoid, and dura mater
Dural Sinus
Instead of an epidural space like the spine, the cerebrum has this; circulates blood and CSF
Faix cerebrii
Extension of the dura mater that sits between the two hemispheres
Faix cerebelli
Extension of the dura mater that sits between the hemispheres of the cerebellum
What is the reason for the folds of the brain
To create more surface area
Gyrus
One tube of the cerebrum
Sulcus
The gaps between the gyri
The lobes of the cerebrum are the same as
The bones that cover them
Instead of sutures, what are the lobes separates by?
Important sulci
Central sulcus
Between frontal and parietal lobes
Lateral sulcus
Between frontal and temporal lobes
Parieto-occipital sulcus
Between parietal and occipital
Cerebrum cortex
Where grey matter is; superficial
Where is white matter in the cerebrum
Deep
Classes of white matter
- Association fibers
- Commissural fibers
- Projection fibers
Association fibers
Axons that carry information to parts of the same hemisphere
Types of association fibers
- Arcuate fibers
2. Longitudinal fibers
Arcuate fibers
Allow communication between two gyrite that are right next to each other
Longitudinal fibers
Axons that allow communication between two distant parts of the same hemisphere
Commissural fibers
Axons that allow communication between the two hemispheres
Locations of commissural fibers
- Anterior commissure
2. Corpus callosum
Projection fibers
Axons that allow communication between the cerebrum and the rest of the body (spine, brain stem)
What do all projection fibers run through
The thalamus (and medulla oblongata)
How is grey matter organized in the cerebrum
In nuclei that are in strips that run across the cerebrum over the left and right hemispheres
Primary sensory cortex
Nuclei of the cerebrum; “postcentral gyrus”; Receives all somatic sensory information; does not interpret that information
Homunculus
“Map” of the parts of a nuclei and what they effect/control
Association areas
Interpret the information; where we store memories about sensations
What do all cortex have?
An association area
Auditory cortex
Receives sensory information about sound
Auditory association area
Interprets the auditory information
Primary motor cortex
“Precentral gyrus”; All of your conscious muscle movement stems from here; Recieves all motor sensory information; does not interpret it
What would happen if a stroke effected the visual cortex
They wouldn’t be able to read
Somatic motor association area
“Premotor cortex”; stores memories about muscle movements; Interprets the information about motor movements; controls the primary motor cortex; these are learned movements
