Nervous Class Notes

• Generate info on dendrites, send through AXONs

  • Axon sends info AWAY —> efferent

  • Dendrites send info INTO —> AFFERENT

• ONLY 1 AXON!!! No matter how many dendrites

• Some axons have myelin sheaths

  • Myelin is made of fat

• Gaps between myelin is the nodes of ranvier

  • bare axon

  • axon is like a straw —> meaning it has intra and extra cellular space

• when the cell is at rest, there is 10x more sodium outside than inside, and 10x more potassium inside than outside

  • Resting membrane has POTENTIAL

• Nerve is polarized —> internal negative, external positive

  • how is internal negative when K is positive? other objects are negative inside the cell

• STIMULUS irritates the nerve —> sodium gates fly open —> releases sodium inside through diffusion (no energy required)

  • potassium cannot get through —> sodium is smaller

  • chnages the charge —< depolarization

  • influences the next segment; making gates open, etc, etc

• THE SAME STIMULUS opens potassium gates, but SLOWER —> gates open, making nerve more negative inside and more positive outside —> RESETS TO ORIGINAL

  • repolarization —> resets the charge to what it was like at rest

• ATP needed for Sodium potassium pump —> forces sodium back out

  • If only diffusion occured, then sodium and potassium woudl reach equilibrium and you would die —> never able to send another signal

• when at rest, -70 millivots

  • - 70 charges compared to outide

• nerve signal

  • electrical (change the charge)

  • binary (all or nothing)

  • like dominoes

  • propagate signal

  • set back up

• Refractory prd: A period of time where you cannot send another

• destroys receptors —> when too much stimulus and cannot control

  • tolerance

Cranial Nerves

• Rostral: Towards the front of the brain (towards the nose)

• Caudal: Towards the back of the brain (towards the tail)

• Numbers go from rostral to caudal 1-12

CRANIAL Nerves:

OLd OPrah OCcasionally TRies TRIGonometry And Feels very gloomy and hypoactive

Some say money matters but my brother says big brains matter most

1. Olfactory n.

   1. Sensory - Smell

2. Optic n.

   1. Sensory - Sight

3. Oculomotor n.

   1. Motor - Superior rectus, medial rectus, inferior rectus, inferior oblique, levator palpabrae, intrinsic eye muscles (changes pupil size)

   2. Does NOT sense light

   3. Moves eyeball inside the socket

      1. 4 of the 6 muscles

4. Trochlear n.

   1. Motor - superior oblique

   2. Moves eye

5. Trigeminal n.

   1. Sensory - to head and neck

      1. Uses the three pairs of holes in skull (supraorbital, infraorbital, mental)

   2. Motor - mastication muscles

6. Abducent n.

   1. Motor - Lateral rectus

   2. Moves eye

7. Facial n.

   1. Sensory - Taste; anterior 2/3 tongue

   2. Motor - Facial muscles, lacrimal glands, submandibular, sublingual salivary glands

8. Vestibulocochlear n.

   1. Sensory - Sound and balance

9. Glossopharyngeal n.

   1. Glosso = Tongue; Pharyngeal = Neck

   2. Sensory - Taste; posterior 1/3 tongue

   3. Motor - Parotid gland and pharyngeal muscles (swallowing)

10. Vagus n.

    1. Sensory - taste; palate and pharynx visceral sensation

    2. Motor - Visceral organs

    3. Only cranial nerve which leaves the head and neck

       1. Vagus = Wanderer

11. Accessory n.

    1. Motor - SCM and trapezius

12. Hypoglossal n.

    1. Motor - Tongue

Coverings:

• Bone - Skull and spine

• Epidural space (fat) - Spine is cushioned with fat

• Meninges -

• Cerebral spinal fluid

Pia mater —> Clings around

Sub arachnoid space —> blood vessels and csf

Dura mater —>

CSF inside brain

• Every sugar you eat, you age

pain is ipsilateral

The BRAIN:

• Cerebellum

  • Cortex

• Diencephalon

  • Thalamus, hypothalamus, epithalamus

• The brain stem

  • Midbrain, pons, medulla, cerebellum

• The cerebrum —> Gyrus/gyri = The bumps; Sulcus/sulci = Grooves

  • Central sulcus —> Everyone has it;

  • Longitudinal fissure —> Splits brain into hemispheres

  • Corpus Collosum —> biggest “highway” between hemispheres in the brain

    • Any “highway” that connects the two hemispheres is called a commoseur

  • Lobes

    • Frontal —> Move and reason

    • Parietal —>

    • Occipital

    • Temporal

      • Like the thumb of a boxing glove

      • Can be moved

    • Insular Lobe

      • Under temporal lobe

• The motor areas

  • Primary motor cortex

    • In front of central sulcus

    • Gives movement, but not planned

  • Pre-motor cortex

    • In front of primary motor cortex

    • Plans the movements

  • Broca’s area

• Sensory areas

  • Primary somatosensory cortex

  • Primary visual cortex

  • Primary auditory cortex

  • Olfactory and and gustatory cortex

• The associacion areas

  • Somatosensory associacion cortex

  • Visual association cortex

  • Auditory association cortex

  • Prefrontal cortex

  • Wernicke’s area —> Language interpretation

  • Facial recognition area (R)

Diencephali:

• Thalamus:

  • Conduct sensory impulses to the c ortex

  • Conduct motor impuses to the cerebellum

  • Mediates sensation, motor activities, learning, and memory

• Hypothalamus

  • Autonomic control

  • Emotional response

  • Body temperature

  • Food and water intake

  • Sleep wake cycles

  • Endocrine (Pituitary)

• Epithalamus

  • AKA Pineal gland

  • Secretes melatonin

Brain Stem: Autonomic, life necessary functions

• Midbrain

  • Consciousness and arousal

  • Visual and auditory reflexes

  • Control askeletal muscle

  • CN III and IV

• Pons —> Relay station (Similar to thalamus)

  • Connect cerebrum to cerebellum

  • Respiratory control (PRG) —> Controls depth of breathing —> How LONG you are breathing

  • CN V, VI, and VII

• Medulla

  • Respiratory control (DRG and VRG) —> Controls RATE —> How many TIMES you breathe

  • Cardiac control —> Influence the heart by speeding up and slowing down the heart

  • Vasomotor actions

  • Vomiting, sneezing, coughing…

  • CN VIII, IX, X, XI, and XII

• Cerebellum

  • Processes information from cerebrum

  • Cognition and language processing

  • Smooths out and coordinates skeletal muscle contraction