LAB Flashcards
Why don’t axons touch?
They are insulated so they don’t stimulate themselves
4 Main spinal plexuses
Lumbar, brachial
Divergent neuronal track
One neuron diverges into many
Converging circuit
Many neurons converging to one (Many factors playing into single decision)
Reverberating
Multiple neurons that go in a positive feedback loop
Parallel
One neuron generally breaks into many parallel lines going at once (Activities that require many actions at once)
What is a voluntary reflex?
Involves skeletal muscle - the ability to override it.
Two different types of reflexes
Somatic and autonomic
What is an autonomic reflex?
A reflex that you cannot overcome?
Difference bw spinal reflex and cranial?
Spinal mediated by spinal nerves
Cranial mediated by brain
BUT not ALL spinal reflexes go to the brain
Learned reflexes?
Driving sports etc.
For protection but can use to our advantage in sports
5 components to a reflex
- Receptor (A stimulus generates a response)
- Sens. Neuron
- CNS (gray matter in Spinal Cord)
- Motor Neuron
- Effector
Receptors in muscles do what?
Ensures muscle is not too stretched or too relaxed`
Where is an AP generated?`
Axon Hillock
Monosynaptic reflex (example)
No interneuron involved - one synapse bw motor and sensory
Ipsilateral
The same side of the body
Receptor in knee-jerk reflex
muscle spindle receptor
Reciprocal innervation
When the agonist is stimulated the antagonist is inhibited (relaxed)
When there are 2 or more synapses
Always involve an interneuron
Polysnaptic
Rami/ramus
Branches
How many and how are connections made in the brain?
100,000 trillion connections made through stimulation throughout life
How is the brain stimuated?
By challenging it
1 cubic mm of brain tissue contians
1 billion connections
The total length of nerve fibers is to
More than 500,000kms
Speed of AP
40m/s (144kph)
Without a constant supply of glucose and O2 to the brain
Loss of consciences
Mysteries of brain
Spoken language in all its forms
Morality
Consciences
Memory and memory retrieval
Facial expressions (Smiling vs fake smiling= different part of brain)
6 basic emotions
Surprise, fear, anger, fear, disgust, happiness, and sadness
Major Brain Regions
Brain stem
Cerebellum (little brain)
Diencephalon
Cerebrum
Brain stem
Connects the spinal cord to the brain
Midbrain
Pons
Medulla Oblongata
Medulla Oblongata
- Myelinated axons
- Relays impulses
- Centers for HR+Breathing regulation
- Carries nuclei (cell bodies of cranial nerves VIII-XII
Pons
Relays impulses
Assists medulla with breathing
Nuclei cranial nerves V-Viii
Midbrain
Relays impulses via cerebral peduncles (anterior)
(Colliculi) Corpora quadrigemina (posterior)
- Responsible for visual + auditory reflexes
0 Coordinates hey movement
Remainder of Cranial nerves
Cerebellum
Hemispheres, folds, arbor vitae, cerebellar cortex
Coordinates movement
Balance and posture
Compares intended movement with actual movement and corrects it
How does alcohol affect the brain?
Lowers function of the cerebellum
(Standing, posture, speaking)
Crosses BBB
Affects the WHOLE brain
Drinking and pregnant
Alcohol affects the baby developing bc it means that the babies brain is going to develop incorrectly or slowly etc/
Diencephalon
Thalamus, Hypothalamus, Epithalamus and pit gland
Hypothalamus
ANS and Pit Gland
Motherboard for endocrine glands
- Body temp, hunger/thirst
- Sleep
Pituitary Gland
Hangs by little stock on the bottom of the brain
- Produces hormones
- Regulated by hypothalamus
- Hormones go into the bloodstream therefore pit gland is surrounded by capillaries
Thalamus
Relays all impulses to the cerebral cortex
- Relay station for sensory impulses (except for smell)
RAS
Reticular Activating System
Maintains consciousness
- Wake up from all senses but smell
- Alarm clock
Cannot pinpoint location
Epithalamus
Including Pineal Gland
Releases hormonal gland melatonin
Controls sleep pattern
As you sleep your brain produces less melatonin and you wake up
The Cerebrum
Two halves
Connected by Corpus callosum
- Functional connection, myelinated axons running from R to L (Commissural) fibers
Where are projecting fibers found?
Vertical fibers in spine and brain
Projecting fibers
Found in white matter in the cerebrum
How are the brain and spine opposite ?
White and gray matter is switched
Basal Ganglia
Concentrations of cell bodies deep within the brain
Coordinate large automatic muscle movements and involved in the limbic system of the brain
Help initiate and terminate motor movement’
And initiate and terminate emotional behaviour
The body suffocates basal ganglia in HD patients end up with a “hollow brain”
5 Lobes separated by folds
Frontal, parietal, temporal, occipital and inner insula (Behind temporal lobe)
Function of cerebrum
Motor, sensory, and association (interactive) Function
Motor controls skeletal muscles
Sensory areas receive and interpret impulses
Association areas perform complex integrative functions involving emotional and intellectual functions
Protective layers of the brain
Same as the spinal cord
Where is CSF Located and produced?
In the four ventricles
Intraventricualr foramen
Brings CSF from lat to 3rd ventricle
Cerebral aqueduct
BRings CSF from 3rd to 4th ventricle
What does CSF do?
Nuritionment, homeostasis, mechanical cushioning
Ependymal cells
Produce fluid lining ventricles
Be familiar with the flow of CSF
4 types of brain waves
Alpha, beta, theta, and delta
Vary in age and on activity
Lots of delta waves indictive of
low brain activity
Cranial Nerves
12 emerge from bottom of brain
1 Olfactory S
2 Optic s
3 Oculomotor m
4 Trochlear m
5 Trigeminal b
6 Abducens m
7 Facial b
8 Vestibocochlear s
9 Glossopharangeal b
10 Vagus b
11 Accessory m
12 Hypoglossal m
Thin layer that Separates lateral ventricles
Septum pellucidum
Cranial Nerve I
Olfactory: Smell
Cranial Nerv II
Optic: Vision
Cranial Nerve III
Oculomotor: Movement of four eye muscles, eyelid, lens accommodation and pupillary constriction
Cranial Nerve IV
Trochlear: Superior oblique muscle of eyeball
Cranial Nerve V
Trigeminal: Opthalamic branch (cutaneous sensations) maximally and madible areas, chewing
Cranial Nerve VI
Abducens: Lateral rectus muscle of eyeball
Cranial Nerve VII
Facial: Taste, anterior 2/3 tongue (Salivation), facial expression, secretion of tears
Cranial Nerve VIII
Vestibulocochlear: Equilibrium and hearing
Cranial Nerve IX
Glossopharyngeal: Posterior third of tongue
- Swallowing, speech, secretion of saliva
Cranial Nerve X
Vagus: Taste, swallowing, coughing, voice production, Contraction of GI tract, slows HR, secretion by digestion glands
Cranial Nerve XI
Accessory: Swallowing
Cranial Nerve XII
Hypoglossal: Tongue muscles, Speech and swallowing
Basal Nuclei AKA
Corpus striatum
General Senses
Touch, pain, pressure
4 necessary events for sensation
Stimulus
Transduction (receptor changes stimulus into receptor potential)
Conduction (AP goes to CNS)
Integration: In CNS - interpretation occurs
What is transduction
(receptor changes stimulus into receptor potential)
Where are the cell bodies of the cranial nerve located?
In brainstem
Projection
Brain refers to sensation to a learned point of origin
Phantom pain
Funnybone
Funny bone?
Ulna nerve being stuck that ends in pinky and ring finger (Anytime brain relieves signal from ulna nerve it thinks it’s from the fingers)
Adaptation
Stimulus remains the same but the sensation changes (decreases)
AP decrease or stop
- The threshold increases (quickly)
- Receptor threshold changes
Afterimage
Stimulus is gone but sensitivity still present
- Only happens in special senses
Bipolar neurons that are overstimulated have synapses in organ which involve chemicals which don’t go away immediately when the stimulus is taken away
Special sense neurons are
Bipolar
Modality
Each receptor sensitive to its own specific stimulus
EXCEPTION: Pain
Too much stimulus hurts
Receptive Field
Stimulus only able to stimulate receptors within a certain range/ receptive field (Soft touch, UV light, bland taste etc.)
Hair purpose
Promote wound healing (Skin heals from below the hair)
Purpose of layered corpuscle
Determine degreee of pressure
Only part of brain with thermorecepyors
Hypothalamus
6 basic emotions
surprise, anger, fear, disgust, happiness, sadness
medulla
relays sensory and motor impulses
between brain and spinal cord
Contains vital centers for heartbeat
regulation and breathing
Nuclei cranial nerves VIII - XII
Pons
relays impulses to and from the
cerebellum, medulla, and midbrain
Helps control breathing
Nuclei cranial nerves V -VIII
Midbrain
relays impulses via cerebral
peduncles (anterior)
corpora quadrigemina (posterior)
responsible for visual and auditory
reflexes
(Coordinates eye movement, head,
and trunk movements due to
auditory stimuli)
Nuclei cranial nerves III + IV
Folia
folds of the cerebellum
arbor vitae
White matter of cerebellum
Gray matter of cerebellum
cerebellar cortex
cerebellum
Balance and motor coordination
regulates posture and balance:
compares the intended
movement with the actual
movement and corrects for
it.
Hypothalamus
Control autonomic nervous system and pituitary gland.
- Controls visceral activities like body temperature, eating and
drinking behaviour, sleep, body temp. etc.
Thalamus
Relay station for all sensory impulses to the cerebral cortex.
(except smell)
Epithalamus
superior and
posterior to thalamus, includes
pineal gland (endocrine gland)
secretes melatonin - controls
sleep, sets our biological clock
Projecting fibers
White matter connecting cerebrum to spinal cord
Association fibers
Sulcus to sulcus (Same hem) white matter comunications
What is the cerebral cortex made up of ?
Cell bodies
Basal Ganglia
Cell bodies deep
coordinate large, automatic muscle
movements and regulate muscle
tone.
- involved with the limbic system or
emotional brain.
Simply put: they help initiate and
terminate movements and
emotional behaviour, and allow us
to set boundaries for both.
Association areas of the brain role
perform complex
integrative functions involving
emotional and intellectual
processes.
RAS
- waking up, maintaining
consciousness (is NOT the same
as setting our biological clock. This
is an alarm clock.)
Through thalamus
Primary gustatory area located where?
Furtherest corner of somatasensory cortex
center of side of brain
Parietal/temporal area
Where is Broca’s area
Frontal Lobe
Lower right
Where is Wernicke’s area?
Parietal near occipital and temporal
Primary visual area
Very back and bottom of brain
Brain waves
Alpha: 8 – 13 cycles/sec (Hz)
relaxed, eyes closed
Beta: 14 – 30 Hz
tension, mentally active,
eyes open
Theta 4 – 7 Hz: drowsiness, emotional stress
Delta 1-5 Hz: deep sleep, serious brain
disorders, young infants
Draw Cranial Nerve picture
https://quizlet.com/410473644/cranial-nerve-face-diagram/
Label cranial nerves on diagram
Which neuroglial cell helps wit the regeneration of axons
Schwann cell
general sensory info originate from?
Somatic sensory receptors (skin and skeletal muscles) or viscerral sensory receptors
Structural classes of general receptors?
Free nerve endings, encapsulated nerve endings, or specialized receptor cells
Free nerve endings
Class of general receptors that are not associated with sensory structures, free nerve endings are dendrites of sensory neurons coveys senses of tickle, itch, and some touch
Encapsulated Nerve ending
Dendrites of sensory neurons enclosed by a connective tissue capsule conveying general sensations of touch pressure and vibration
Type 1 Cutanous receptor
Merkel disc mechano receptor
- Tactile epitheleal cells in epidermis
-Free nerve endings
-Slow adapting
-Continuous touch/pressue
Dendrite at surface
Type 2 Cutaneous receptor
- Dermis ligaments, and tendons
Encapsulated nerve endings - Skin stretching + pressure
- Slow adapting
Dedrite deeper in skin
- When a person experiences a heart attack, why is there pain down the left arm?
Answer: The pain in the visceral organ (heart) is felt as referred pain. The somatic sensory fibers of the left arm share the same entrance to spinal cord (dorsal root ganglion) as the visceral sensory fibers of the heart.
Why would pain persist even after the stimulus is removed?
Answer: pain could persist because pain mediated chemicals linger and nociceptors exhibit very little adaptation
Sensory neurons from general sensory receptors are
unipolar
Corpuscle of touch describe
Gandolf staff near the surface
Hair root plexus
Bottom of hair root
Where can referred pain for the liver and gallbladder appear
Right neck
And lower right abdomen
Lung and diaphragm referred pain
neck
Lammellated corpuscle
Pacinian corpuscle
Circular looking
Deep dermis
Large
Example for What a diverging circuit for
Visual information form eyes to CNS then distributed to areas of brain to control
posture
Categories of reflexes
Somatic, autonomic or visceral;
Ipsilateral or contrlaterl ior bilateral
Cranial or spinal
Organ responsible for achilles reflex
GTO
Hyporeflexia
temporary or permanent
damage to skeletal muscles, dorsal or ventral nerve roots, spinal nerves, spinal cord
or the brain.
(decreased reflex)
areflexia
No reflex
Polio
- destroys the cell bodies of motor neurons especially those of the anterior horns
in the spinal cord and/or nuclei of cranial nerves – resulting in paralysis (loss of somatic
reflexes) and even death, depending on the area affected.
Shingles
– acute infection of PNS by Herpes roster (chicken pox). The virus retreats to the
posterior root ganglion – if the virus is reactivated a healthy immune system prevents it from
spreading. A weakened immune system may enable the virus to travel down a sensory
neuron by “fast axonal transport” creating the characteristic blisters of shingles. The
affected nerve would have hyporeflexia.
Huntingtons disease chorea
a rare hereditary disorder caused by an autosomal
dominant trait meaning that if the person carries one affected gene they will develop the
disease usually between 35-40 years which gradually progresses over the next 15-20 years
eventually resulting in death. The genetic defect produces a defective protein that
suffocates the basal ganglia resulting in progressive motor incoordination, abnormal
involuntary movements, and intellectual decline. This also leads to hyporeflexia
ALS
– a pregressive death of the cellbodies of motorneurons will also result in hyporeflexia. Which reflexes will be affected first depends on which motorneurons are affected first.
Major nerves from Cervical, brachial, lumbar, sacral and coccyx
4 events necessary for stimulus to be detected
stimulus, transduction, conduction, integration
Projection
brain refers sensations to their learned point of
origin
Afterimage
stimulus is gone, but sensitivity still present
- Chemicals in synapses still present, dont dissapate immediately
Receptive field
Receptor only able to sense stimulus within certain range (hz, pressure, volume etc.)
Know referred pain diagram
textbook 576
What is the structure of a speciality sensory neuron
Specific (i.e gustatory ) receptor generates GP and synapses with first order neuron
Difference bw lamellated corpuscle and Meissner corpuscle
M is located near surface of epidermis and is smaller
-Fine touch and pressure
L is deep dermis and is larger
- pressure + fast vibration
How does the Pacinian corpuscle structure aid in it’s function
Layers allow it to grade level of pressure
Memorize muscle fiber
