Week 3 - Central and Nervous System Flashcards
The main difference between ganglia and nuclei is that ganglia are clusters of nerve cell bodies in the PNS whereas nuclei are clusters of nerve cell bodies in the CNS
cns
3. Recall the following information about the central nervous system. The:
a) principal organs of the system
the brain and spinal cord
b) general function of each organ
The brain is a complex organ that controls thought, memory, emotion, touch, motor skills, vision, breathing, temperature, hunger and every process that regulates our body.
Your spinal cord carries nerve signals from your brain to your body
neauron
Neurons (also called neurones or nerve cells) are the fundamental units of the brain and nervous system, the cells responsible for receiving sensory input from the external world, for sending motor commands to our muscles
neurogila
neuroglia, also called glial cell or glia, any of several types of cell that function primarily to support neurons
somaitc vs autonomic NS
The somatic nervous system is responsible for voluntary actions, namely the innervation of skeletal muscle. The autonomic nervous system is responsible for all involuntary actions, including smooth muscle contraction, glandular stimulation, and other functions.
afferent vs efferent NS
The afferent or sensory division transmits impulses from peripheral organs to the CNS. The efferent or motor division transmits impulses from the CNS out to the peripheral organs to cause an effect or action
cns vs pns
The central nervous system includes the brain and spinal cord, while the peripheral nervous system includes all of the nerves that branch out from the brain and spinal cord and extend to other parts of the body including muscles and organs
cerebrum
a) location
the large upper part of the brain
b) number of hemispheres Two (left and right)
c) name of the fissure and associated tissues dividing the hemispheres corpus callosum helps allow the two hemispheres to communicate, a deep longitudinal fissure separates the two.
d) name and number of lobes per hemisphere 4 lobes (frontal, parietal, temporal and occipital)
e) general distribution of gray and white matter
40% gray and 60% white (white matter is deep)
f) descriptive terms related to the surface: Gyri- bumps ridges on the cerebral cortex Fissures- large furrow that divides the brain into lobes and also into the two hemispheres as the longitudinal fissure Sulci- a shallower groove that surrounds a gyrus
g) name of the largest commissural tract that connects the gyri in one cerebral hemisphere to the corresponding gyri in the other hemisphere
The corpus callosum
cerebral cortex
a) type of matter
Gray matter
b) location
Outermost of the cerebrum
c) thickness
About 2.5mm
d) surface appearance
Indentated and grooved
4 lobes
frontal
a) the location
Front of the brain
b) the type of matter composing each
white
c) the function(s) in sensation and in movement
Initiates motor impulses to specific somatic effectors of system (i.e.,skeletal muscle) (in Primary motor area) Control voluntary movements of walking, talking, running, writing (in Premotor area)
Paritral
a) the location
Midbrain towards the top
b) the type of matter composing each
white
c) the function(s) in sensation and in movement
- Awareness of general sensations of pain, pressure, temperature, touch, sense of position conscious proprioception. 2. Awareness of taste. Receive impulses Localization/intensity – in primary somatosensory area. Integration-perception-in somatosensory association area
Temporal
a) the location
By your ears/temples
b) the type of matter composing each
white
c) the function(s) in sensation and in movement
Awareness of sound and smell Receive impulse Integration-perception
Occipital
a) the location
Towards the back of your head
b) the type of matter composing each
white
c) the function(s) in sensation and in movement
Awareness of vision Receive impulse Integration-perception
basal nuclei
a) the location
Base of brain
b) the type of matter composing each
4 clusters of neurons, or nerve cells
c) the function(s) in sensation and in movement
Assist with coordination of voluntary skeletal muscle movement by controlling associated subconscious movements which accompany voluntary activity
thalamus
- major relay station for seensory tracts
- crued interpretation of general sensations (pain, temp, touch)
- helps with emotionsa by assoicatinf senesory impulses with feelings of pleasantneess or unpleastness (limbic)
- role in arousal or altering mechanism (RAS)
- helps with emotionsa by assoicatinf senesory impulses with feelings of pleasantneess or unpleastness (limbic)
hypothalamus
- helps miantain waking state (RAS)
- emotions of rage/aggression (limbic)
- detetctions of changes in the internal enironment
- temp via thermorecpetors
- ecf osmotic pressure via osorecpetors
motor:
- major control centre of ANS: regulates activitesof viseral in effectors of system (thirst, appeitie)
- relay station from cerebral cortex to lower control centres in brainstem and spinal cord basis for central cortex infeluence over somatic and viscerak effector organ system
- anatomic connection with pituatioty gland- linking nervous/ endocrine control
brainstem
- conduction pathway from spincial cord to cerebrum
- relay station from cranila nerves to toher parts of brain
- contains (RAS) (sanll areas of grey matter)- function to arouse, alert cortex and hence maintain consious
- reflex centre for craniak nerves (pupil diluations)
midbrain
- in brainstwm
- control centre- reflex centre- for head and eyeball movements in reponse to sound and sight impulses
pons
in brainstem
control centre- pontine rspirartory group- for regulation of rhythm of respirations
medulla oblongata
- brainstem
- vital control centres: cardiac- regulates HR& dtrength of contraction vasometer- regulates blood vessel diameter. repitarory- regulates rate and depth of respiration
- non vital control centres: shallowing, vomiting, coughing, sneezing, hiccoughing
- decussation of major motor projection tracts to skeletal muscle effectors
cerebellum
- acts aubconsciously with cerebral cortex ro prodcue skilled coordinated skeeltal muscle movements
- maintainces of posture/balance
Discriminate between the role of the thalamus and general sensory area of the cerebral cortex in the perception of sensation
The cerebral cortex is where these sensations are formed and perceived, but the thalamus has a lot of the sensory tracts and interpretation aspects that the cerebral cortex lacks
functions of theses definations realting to skeltal muscles, cerebellum,basal nuclei, frontal lobe
i) frontal lobe
Initiates motor impulses to specific somatic effectors of system in the primary motor cortex
ii) basal nuclei
Assist with coordination of voluntary skeletal muscle movement by controlling associated subconscious movements which accompany voluntary activity
iii) cerebellum
Acts subconsciously with the cerebral cortex to produce skilled, coordinated skeletal muscle movements.
RAS
Helps maintain waking state (hypotalamus)
Role in arousal or alerting mechanism (thalamus)
functions to arouse, alert cortex and hence maintain consciousness (brainstem)
Limbic
Helps with emotions by associating sensory impulses with feelings of pleasantness or unpleasantness (thalamus), Emotions of rage, aggression (hypthalamus)
cerebralspinal fluid
a) source of fluid
choroid plexus in the lateral, third and fourth ventricles
b) site and mechanism of formation
Cerebrospinal fluid is produced by a specialized tissue called the choroid plexus. Choroid plexuses are located in the walls of the lateral ventricles and in the roofs of the third and fourth ventricles. A choroid plexus shows numerous villi, via which it secretes the cerebrospinal fluid
c) site and mechanism of reabsorption (to include the superior sagittal sinus)
The majority of the cerebrospinal fluid (CSF) is absorbed into the venous system by the arachnoid granulations.The highest number of arachnoid granulations is found in the superior sagittal and transverse sinuses. Thus, these are the sites where most of the CSF is absorbed.
The main difference between ganglia and nuclei is that ganglia are clusters of nerve cell bodies in the PNS whereas nuclei are clusters of nerve cell bodies in the CNS
THE CEREBRUM
3 branches into whic spinal nerves divide after leaving intervertebral foamina
a) dorsal ramus
The dorsal ramus carries information that supplies muscles and skin sensation to the human back.
b) ventral ramus
carry sensory and motor fibres for the innervation of the muscles, joints, and skin of the lateral and ventral body walls and the extremities
c) meningeal branch
The meningeal branches supply nerve function to the vertebrae themselves, including the ligaments, dura, blood vessels, intervertebral discs, facet joints, and periosteum
circle of willis
anastomotic ring of arteries located at the base of the brain. … The main function of the circle of Willis is to provide a collateral blood flow between the anterior and posterior arterial systems of the brain.
obtaining cerebrospinal fluid
a) name of test
spinal tap
b) level of vertebral column into which needle is inserted
L4/L3
c) reason for needle insertion at the level identified (b)
Since the spinal cord ends as a solid structure around the level of the second lumbar vertebra (L2) the insertion of a needle must be below this point, usually between L3 and L4
d) space into which needle is inserted to obtain fluid
subarachnoid space
ceberocpinal fluid
a) average volume in an adult and newborn
4ml in adult, 2ml newborn
b) average pressure in an adult
c) colour
clear/colourless
d) five constituents
CSF serves five primary purposes: buoyancy, protection, chemical stability, waste removal, and prevention of brain ischemia
e) three functions
CSF performs vital functions including: Support; Shock absorber; Homeostasis;
Nutrition; Immune function
spinial cord
a) body cavity in which it lies
dorsal cavity
b) origin
The spinal cord extends from the foramen magnum to the sacrum in the human fetus at the beginning of the 2nd quarter
c) level of vertebral column at which it ends
The spinal cord tapers and ends at the level between the first and second lumbar vertebrae
d) two functions
It connects your brain to your lower back. Your spinal cord carries nerve signals from your brain to your body and vice versa.
ganglia in PNS vs nuclei of CNS
The main difference between ganglia and nuclei is that ganglia are clusters of nerve cell bodies in the PNS whereas nuclei are clusters of nerve cell bodies in the CNS
4 spinial nerves
i) phrenic
I:cervical plexus
F: receives innervation from the C3, C4, and C5 nerve roots
ii) radial
I: originates as a terminal branch of the posterior cord of the brachial plexus
f:motor (movement) and sensory functions to the arm
iii) femoral
I: lumber plexus
F: motor and sensory processing in the lower limbs
iv) sciatic
I: sacral plexus
F: Motor function: Helps the muscles in your leg and feet move. Sensory function: Helps you feel sensations in your legs
dermatome
A dermatome is an area of skin that’s supplied by a single spinal nerve. Your spinal nerves help to relay sensory, motor, and autonomic information between the rest of your body and your central nervous system (CNS).
sensory cranial nerves
I (one) Olfactory
F: Transmits impulses from olfactory receptors
L:olfactory bulbs
II (two) - Optic
F:Transmits impulses from retina.
l:Thalamus
VIII (eight) - vestibulocochlear
F:Two branches:
i. Cochlear – transmits impulses from Organ of Corti in ear. (Hearing)
ii. Vestibular – transmits impulses from utricle and saccule. ( Equilibrium)
l:Pons and Medulla (Vestibule Nucleus)
mixed cranial nerves
V (five) trigeminal
F:3 sensory branches:
transmits impulses re: touch, pain, temperature from receptors in skin and mucous membranes of head, face, mouth, and tongue.
Proprioceptive sensory axons from the extrinsic eye muscles.
Stimulates muscles of mastication for control of chewing movements. (S)
L: pons
VII (seven ) facial
F:Transmits impulses from taste receptors of anterior two-thirds of tongue.
Stimulates:
a. contraction of facial muscles for facial expression. (S)
b. secretion of: i. lacrimal glands (production of tears) (A)
ii. sublingual glands (production of saliva) (A)
iii. submandibular glands (production of saliva) (A)
L: pons
IX (nine) glossopharyneal
F:Transmits impulses from taste receptors of posterior onethird of tongue. Transmits impulses from baroreceptors and chemoreceptors in carotid sinus.
Stimulates:
a. contraction of muscles of pharynx swallowing (S)
b. secretion of parotid gland saliva (A)
L: medulla
X (ten) vagus
F: Transmits impulses re: pressure, pain, proprioception from receptors in: RESPIRATORY ORGANS: Larynx through Lungs
DIGESTIVE ORGANS: Pharynx through Large Intestine
HEART and AORTA
Stimulates: a. skeletal muscle contraction in pharynx and larynx voice production (S)
b. skeletal muscle contraction in pharynx, larynx and soft palate swallowing (S)
c. smooth muscle contraction:
i. bronchi bronchoconstriction (A)
ii. digestive organs peristalsis, churning (A)
iii. gastric gland secretion digestive enzymes and mucous (A) Inhibits cardiac muscle contraction decreased rate and force of contraction (A)
L:medulla and pons
motor crainal nerves
III (three) Oculomotor
F: Stimulates contraction of:
a. extrinsic eyeball muscles – movement of eyeball and upper eyelid. (S)
b. intrinsic eye muscles (A) i. ciliary muscles: accommodation of lens ii. iris: const
L:midbrain
IV (four) trochlear
F: Stimulates contraction of extrinsic eyeball muscles - movement of eyeball. (S)
L:midbrain
VI (six) abducens
F:Stimulates contraction of extrinsic eyeball muscles - movement of eyeball. (S)
L:pons
XI (evelen) accessory
F: Stimulates contraction of sternocleidomastoid and trapezius muscles head movements. (S)
L:pons
XII (twelve) hypoglossal
F:Stimulates contraction of muscles of tongue speech and swallowing. (S)
L: pons
3 integratingy functions of cerebreum
Sleep and wakefulness (part of Reticular Activating System) Emotional responses (part of Limbic System) Memory, cognitive processes
paritenal lobe somatosensroy area
a) The primary somatosensory area is located in the postcentral gyrus of the parietal lobe. State the following:
i) function related to reception of nerve impulses from sensory pathways
Awareness of taste.
ii) describe the somatic sensory map of the postcentral gyrus
Receive impulses Localization/intensity – in primary somatosensory area. Integration-perception-in somatosensory association area
b) The somatosensory association area is located posterior to the post central gyrus of the parietal lobe.
i) function related to integration, perception and memory
The postcentral gyrus is a prominent gyrus in the lateral parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch.
frontal pre frontal cortex
a) List examples of functions of the prefrontal cortex.
Initiates motor impulses to specific somatic effectors of system (i.e.,skeletal muscle)
b) List examples of possible effects due to bilateral damage to the prefrontal cortices
Not getting the impulses to skeletal muscles, which means no voluntary movement
c) See Appendix IV which:
i) Describes two types of changes occurring in the adolescent brain related to the prefrontal cortex.
ii) What are the implications of these findings?
primary motor centre - frontal
a) The primary motor area is located in the precentral gyrus of the frontal lobe. State the following:
i) function related to controlling contraction of specific skeletal muscle groups.
Control voluntary movements of walking, talking, running, writing
ii) describe the somatic motor map of the precentral gyrus
The somatic motor pathways of the brain and spinal cord are divided into pyramidal and extrapyramidal systems. Both these systems control the motor activities of body through lower motor neurons.
b) The premotor association area is located immediately anterior to the primary motor area. State the following:
i) function related to integration, initiation and memory of complex learned motor activities
Without the initiation and integration of these impulses, there would be no organisation within the motor activities, making it harder to do complex/simple tasks
cerebralspinal fluid cells
ependymol cells - Ependymal cells are ciliated-epithelial glial cells that develop from radial glia along the surface of the ventricles of the brain and the spinal canal. They play a critical role in cerebrospinal fluid (CSF) homeostasis, brain metabolism, and the clearance of waste from the brain.
- ventricles (3,4, lateral)
- aqauducts (cerebral aquaduct)
- both spinal cord
- noursih/protect brain
- senseory cortex (dorsal) partiental
- motor cortex (frontal) ventral - premotor cortex (voluntary movement)
central suclus
sperates frontal/parital
fibre vs tract, neron vs nerve
fibre- nervous pathway in PNS, tract- nervous pathway in CNS
Neuron - 1 nerve cell
nerve- bundle of nerve cells (has blood supply)
DCML pathway
The dorsal column-medial lemniscus pathway (DCML) is a sensory pathway of the central nervous system. It conveys sensation of fine touch, vibration, pressure, two-point discrimination and proprioception (position) from the skin and joints
three neurons invloved:
- 1 order(sensory) - senses touch, vibration, recpetor to brainsteam. peripheral system to medulla oblongata
- 2nd order (integration station)- medulla- thalamus
- 3rd order- thalamus to partiental lobe (sensory cortex)
arms vs leg
- 1st order sensory info goes from upper body snapses with 2nd order neauron at region called the curetus (fasicules)
- if it is the legs/lower body, the region will be called guallilis (fasicules)
corticospinal tract
The Corticospinal tract (CST), also known as the pyramidal tract, is a collection of axons that carry movement-related information from the cerebral cortex to the spinal cord. It forms part of the descending spinal tract system that originate from the cortex or brainstem.
- motor pathway
- motor cortex
- done use ½/3 order nuerons (only sensory pathways)
- upper/lower motor neuron
- decussate (cross over) info from left to right and vis versa
astrocytes
- most abundant, versatile, and highly branched glial cells
- cling to neurons, synaptic ended and capillairies
functions
- support/brace neurons
- play role in exchanges between capillaries and neaurons
- guide migration of young nervous
- control chemical enironment around neaurons
- respond to nerve impulses and neaurotransmitters
- inflence neauronal functioning - partipate in information processing in brain
mircoglial cells
- small, ovoid cells with thorny processes that touch and monitor neaurons
- migrate towards injured nearuons
- can transform to pagocytize mircoorganism and neuronal debris
oligodendrocytes
branched cells
processes wrap CNS nerve fibres, forming insulating myelin sheaths thicker nerve fibres
pyramidal tracts
These tracts originate in the cerebral cortex, carrying motor fibres to the spinal cord and brain stem. They are responsible for the voluntary control of the musculature of the body and face
extrap’yramial tracts
These tracts originate in the brain stem, carrying motor fibres to the spinal cord. They are responsible for the involuntary and automatic control of all musculature, such as muscle tone, balance, posture and locomotio
