What are the parts of the brain?
What is the Cerebrum responsible for?
- Conscious thought
- muscle control
What is the Thalamus responsible for?
Relay for sensor information
What is the hypothalamus responsible for?
- Control of petuitary gland
What is the Midbrain responsible for?
- Visual and auditory data
- Reflex generation
What is the Pons responsible for?
- Sensory relay Cerebellum to Thalamus
- Uncontious information
What is the Medulla responsible for?
- Sensory relay Thalamus to brain stem
- Autonomic regulation of the cardiovascular, respiratory and digestion
What is the Cerebellum responsible for?
- Unconscious proprioception
- Ataxic = Drunker gait
What is the Ventricle system?
Used to provide nutrients through fluid created by the Ependymal cells
- **Ependymal cells within the choroid plexus produce
- cerebrospinal fluid**
- **CSF is needed to help provide support as well as
- nourishment to the cells of the spinal cord to circulation of fluid done via locomotion.**
- ** CSF gets excreted via two foramen which are linked the
- foramen of lushka ( lateral) foramen of Magendii **
- ** The fluid is then reabsorbed by arachnoid mater
- granulations and emptied into the superior sagittal sinus**
What are Protective Coverings in the brain?
**Due to importance brain is covered by connective tissue (Fascia)**
Fascia between the hemispheres---Falx cerebri
Fascia that covers the cerebellum-tentorum cerebelli, falx cerebelli
How many protective covering do the Spinal cord and Brain have and what are they?
Spinal cord and brain have 3 protective coverings and 2 spaces
- Dura mater---protective outer covering
- Subdural space
- Arachnoid mater---circulation CSF
- Subarachnoid space---CSF is reabsorbed
- Pia Mater---- anchors the spinal cord into the spinal canal
- Denticulate ligaments
Describe the Cerebrllum
- “Arbor Vitae”- tree of life
- Composed of Purkinje type nerve bundles to act as a relay of the spinal cord tracts to the cerebrum
- 3 peduncles- bridges to allow for the relay
- **Superior--connects to the -cerebrum, thalamus**
- **Middle--connests to the -Pons, midbrain**
- **Inferior--connects to the -medulla, and spinal cord**
Discribe the Cerebrum
- Certains of higher thought
- Subdivided into sections
- a. frontal lobe
- b. precentral gyrus---motor control of muscles
- c. postcentral gyrus----sensory control of muscles
- d. parietal lobe
- e. occipital lobe
- f. temporal lobe---below the lateral sulcus
Describe the Temporal Lobe
- Thalmus Subdivided based on sensation it picks up
- Anterior group- sensation to limbic system
- Medial group—frontal lobe
- Lateral group- parietal lobe and cingulate gyrus
- Ventral group-basal nuceli, cerebellum, general sensory
- Posterior group-(pulvinar)
- a. medial geniculate—visual
- b. lateral geniculate-auditory
- Emotional system memories
**Describe the Limbic System**
- Memory formation, emotional as well as sensory.
- Cortical: cigulate, dentate, parahippocampal yggyri)
- Nuclei: hippocampus-long term memories storage and retrieval.
- Amygdaloid body---controls heart rate in fight or flight response
- Connections with the thalmus, hypothalamus and
- the reticular formation
- **Cigulate gyrus is the main component of the limbic system**
**Describe the Commissures System**
Communication connections between hemispheres
The right sensations get interpreted on the left side
Fiber that connects one hemisphere to the other
**What are the Broadmann areas?**
Area 44: Brocas area: speech
Area 41: auditory
- Area 40, 39: wernickes area- all sensory info
- vision, speach, etc
**Describe the Brain Activity**
Due to nerve impulses in the brain there are 4 distinctive waves
Beta- intense concentration
- Theta- children and frustrated adults.. In adults tumor
Delta- deep sleep,,,, if in awake state in adults signifies brain damage
Waves recorded on electroencephalogram (EEG)
What is Cranial Nerve 1, and what does it do?
- Olfactory (sensory)
- Relays the sensation of olfaction
- Sensory fibers run through the cribniform plate of the ethmoid bone to the olfactory bulb
- Anosmia = lack of smell, it is a non functioning CN1
What is Cranial Nerve 2, and what does it do?
- Optic (sensor)
- Sense of vision
- Crosses behind the hypothalamus (optic chiasma) chiasma means cross
- Test: Snellen eye chart (20/20)
- CN2 pathology: Blindness
What is Cranial Nerve 3, and what does it do?
- Oculomotor (motor)
- Controls movement to the intrinsic eye muscles
- **Medial rectus, superior rectus, inferior rectus, inferior oblique**
- Ganglia: ciliary goes to the lacrimal gland
- Pupillary light reflex
- **Test: Cardinal points of gaze**
What is Cranial Nerve 4, and what does it do?
***Only Cranial nerve which crossed outside of the midbrain****
**Innervates the Superior oblique (down and out)**
What is Cranial Nerve 5, and what does it do?
- **Ganglia (sensor/motor)**
- Trigeminal (3 ganglia)
- Motor and sensory to face
- 3 branches: Opthalmic, Maxillary and Mandibular
- ***Mandibular is motor***
- Tic Douloureux---Trigeminal Neuralgia-lancinating electric shock like pain (disabilitating desease)
- herpes Zoster virus---lies dorment in the ganglia (stress induced)
What is Cranial Nerve 6, and what does it do?
Innervates the Lateral Rectus (look to the side)
- LR6 SO4 all over 3
- Lateral Rectus CN6/Superior Obique CN4 and all other eye muscles CN3
- SR - look up
- IR - look down
- MR - look in
- LR - look out
- SO - down and out
- IO - up and in
What is Cranial Nerve 7, and what does it do?
- Sensory and Motor
- 5 Divisions:
- **Geniculate ganglia, pterygopalatine, submandibular**
- Motor to muscles of facial expressions
- **Bells palsy - paralysis of facial muscles and loss of taste to the anterior 2/3 fo the tongue
What is the Cranial Nerve 8, and what does it do?
- Vestibulococchlear (sensory)
- *Vestibular - balance and equilibrium*
- *Cocchlear - hearing (audition)*
- Test: Mittelmeyers march for balance
- Hearing test
What is Cranial Nerve 9, and what does it do?
- Glossopharyngeal nerve (sensory)
- Taste to the posterior 1/3 of the tongue (sensation of bitter)
- Superior ganglion (Jugular)
- Inferior ganglion (petrosal)
- Otic ganglion (parotid gland)
- Ganglion have baroreceptors (pick up pressure) and chemoreceptors (pick up chemicals CO2 and O2) to monitor blood pressure
- (Bitter back 9) easy way to remember
What is Cranial Nerve 10, and what does it do?
- Vagus (sensory and motor)
- Innervations heart, lungs, digestive system
- Test: gag reflex, swallowing reflex
- Everything happens in vagus
What is Cranial Nerve 11, and what does it do?
- Motor to muscles of the neck and upper back
- Spinal accesory nerve
What is Cranial Nerve 12, and what does it do?
- Movement of the tongue
What is the Detection of the Stimulus?
- The receptors pick up specific sensations and relay them to the brain.
- The receptors under constant stimuli undergo adaptation--reducing the sensitivity
- Fast-adapting: respond to sudden changes
- Slow-adapting: respond slowly
What are the Nociceptors?
- Free Nerve Endings (unmylenated)
- Substance P (pain)
- Fast pain: pricking pain (Type A Nerve)
- Slow pain: burning pain (Type C Nerve)
- Release substance P (glutamate) as a neurotransmitter (pain receptors)
- Turnes off by the endorphins/enkephalins (pain gating) (shuts off pain)
What are Thermoreceptors?
- Free nerve endings in the dermis
- 3 to 4 times more cold receptors
- Pick up temerature changes
What are Mechanoreceptors?
Respond to changes in the plasma membranes of the cell
- 4 Types:
- Tactile Receptors - touch, pressure, vibration (Pacinian corpuscle)
- Baroreceptors - detect pressure changes in blood vessels (CN9)
- Proprioceptors - monitor joints and skeletal muscles (detect whether standing, sitting, etc)
- Chemoreceptors - chemical changes
What are Tactile Receptors?
- Free Nerve -touch and pressure
- Root hair - distortions of the hairs
- Tactile disc - Merkel - fine touch and pressure
- Tactile corpuscle - Meissner's corpuscle - fine touch, pressure, low frequency vibration
- Lamellated Corpuscle - Pacinian corpuscle - deep pressure, fast adapting
- Ruffini Corpuscle - sensitive to pressure and distortion of skin
What are Baroreceptors?
Pressure detection located within the elastic tissue walls of blood vessels
Detects in the carotid and aortic sinus
Proprioceptors goes through the Trackus cuneatos and Gracilis (dorsal white column to cerebellum)
What is Spinothalamic Pathway?
***Crude touch and pressure sensation***
Sensation on the left gets interpreted by the right
Anterior and lateral spinothalamic tract (2 tracks, temp. and pain)
What is omunculus?
Map of receptors that pick up sensations of the pathways
What disease is anosmia?
Non functioning of Cranial Nerve 1 (olfaction)
Lack of smell
What pathology is involed with Cranial Nerve 2?
Crainial Nerve 2 Pathology
What disease is Tic Douloureux?
Cranial Nerve 5 (Ganglia)
lancination electric shock like pain (disabilitation desease)
What is Herpes Zoster virus?
Cranial Nerve 5
Lies dormant in the ganglia
What is Bells Palsy?
Paralysis of facial muscles and loss of taste to the anterior 2/3 of the tongue
Cranial Nerve 7
Name the Embryonicall from 3 vesicles
- Prosencephalon (Pro)
- Mesencephalon (Mes)
- Rhombencephalon (Rho)
After the 6th week, how do the vesicles differentiate into 5 vesicles?
- Pro--telencephalon (cerebrum and lateral ventricle)
- Pro--diencephalon (diencephalon and 3rd ventricle)
- Mes--Mesencephalon (midbrain and cerebral aqueduct)
- Rho--metencephalon (cerebellum, ponsand 4th ventricle)
- Rho-- myelencephalon (medulla oblongata and 4th ventricle)