1. Cord itself ends at L1-L2.

2. Lower nerves dangle down in the Cauda Equina.

3. There are 31 pairs of spinal nerves.

4. A spinal segment is what gives rise to one spinal nerve.

5. C1-C7 Spinal nerves project above  C1-C7.

6. C8 Spinal nerve projects below C1-C7 vertebra.

7. T1-S5 spinal nerves project below T1-S5 vertebra.

1. Grey Commissure- cross bar of the H.

2. Central Canal- hole in the center.

3. Anterior (ventral) horns

4. Posterior (dorsal) horns

5. Lateral(intermediate) horns

1. Anterior column

2. Posterior Column

3. Lateral Column

4. Fasciculi/tracts- axon bundles w/common function

a. ascending tracts - sensory to the brain

b. descending tracts - brain--> motor neurons

Fasciculus gracilis

Fasciculus cuneatus

Posterior spinocerebellar

anterior spinocerebellar

subconscious propriorecption

• anterior (ventral) spinothalamic
• lateral spinothalamic tract
• fasciculus gracilis
• fasciculus cuneatus
• posterior spinocerebellar
• anterior spinocerebellar                

Lateral corticospinal

Anterior corticospinal

• Lateral corticospinal
• Anterior corticospinal
• Rubrospinal
• Tectospinal
• Vestibulospinal
• Lateral reticulospinal
• Medial Reticulospinal

• Dorsal root
• Dorsal root ganglion
• Ventral root

Motor nerve axons only

• skeletal motor neurons (ant. horn)
• smooth/cardiac/gland neurons (lat.horn)

1. A special type of conduction pathway

2. Receptor - responds to internal/external stimuli.

3. Sensory Neuron - passes impulse to CNS

a. impulse sent along nerve from that organ.

b. eventually reaches dorsal ramus of spinal nerve

c. synapses on neuron sometwhere in the grey matter

4. Center - point in the CNS where message is accepted.

a. sometimes directly to the effector motor neuron

b. most times on an INTERNEURON of dorsal horn

c. passes message to motor neuron in VENTRAL HORN

d. or passes message to brain via specific tract

5. Motor neuron - sends to signal to appropriate effector.

a. resides in anterior horn - skeletal muscle

b. resides in lateral horn - smooth/cardiac/gland

6. Effector Organ - organ effected by motor neuron

a. simple reflexes an motion - skeletal muscle

b. general physiological - other organs

A. Arterial Supply

1. ascending aorta -> left coronary artery ->

a. Anterior interventricular branch

b. Circumflex branch

2. Ascending aorta -> right coronary artery ->

a. Posterior interventricular branch

b. marginal branch

B. Venous return : Coronary Sinus -> Right Atrium

1. Tributaries contributing to the coronary sinus

a. great cardiac vein (drains anterior)

b. middle cardiac vein (drains posterior)

1. Anteriorventricular Valves

• tricuspid valve - between right atrium and ventricle
• biscupid valve - between left atrium and ventricle

  a. chordae tendinea - attach the cusps to the muscle

  b. papillary muscles - pull on the cusps

2. Semilunar Valves - between ventricles and vessels

a. pulmonary semilunar valve - pulmonary trunk

b. aortic semilunar valve - aorta

When blood leaves the body, it goes via the Left Ventricule to entire body via:

Ascending aorta

(consisting of)

• coronary arteries
• arch of the aorta
• thuracic aorta
• abdominal aorta

pulmonary trunk

• right and left pulmonary arteries
• only arteries with unoxygenated blood.

Venous return of blood to the Right Atrium is via:

• superior vena cava - from areas above the heart
• inferior vena cava - from areas below the heart
• coronary sinus - from the heart muscle itself

• epicardium - visceral layer of pericardium
• myocardium - heart muscle itself
• endocardium - thin endothelium lining inside

What is the pericardium?

It is the Inflammation of the pericardium

 outer thick fibrous layer

• touch bag that surrounds the heart
• attached to diaphragm
• continuous with great vessels

1. right and left atria- upper chambers

• auricles - dog-ear like appendages
• pectinate muscles - bundles of parallel fibers

2. Interatrial septum

• fossa ovalis - closed foramen ovale of fetus

3. right and left ventricles - lower chambers

4. coronary sulcus - exterior groove dividing chambers

5. Anterior and Posterior interventricular sulci

• primary organ of the media stinum
• 2/3 lie left of the sagittal plane
• size of a human fist
• between the sternum and thoracic vertebra.

What is the heart's superior border?

decreased sensitivity to repeat stimuli

• ie. rapidly adapting - pressue, touch, smell
• slowly adapting - pain, position, blood chemicals

response to external environment

(Location of receptors)

response to internal environment

(Location of receptors)

Response to body position/ motion

(Location of receptors)

any mechanical deviation

• ie. touc, pressure, vibration, proprioception etc

shapes of different molecules

• i.e, taste, smell, chemicals of blood

(type of stimulus detected)

• light touch (location not perceived)
• discriminative touch (location perceived)
• Merkel's discs (discriminative touch)
• organs of Ruffini - deep, continuous touch

• felt over a large area than touch, much deeper
• Pacinian corpuscle - lower layers of dermis

• acute pain (very quick, not felt in deep areas)
• chronic pain (longer lasting, gradual increase)
• somatic pain (skin, muscles, joints) superficial - skin, deep - muscle, joint, tendon, fascia

function- position of limbs/body & equilibrium

muscle spindles

intrafusal fibers - inner muscle fibers

type Ia sensory - in center

type II sensory - at ends

Gamma motor neuron - from ventral horn

extrafusal fibers - outer muscle fibers

Alpha motor neurons - form ventral horn

Golgi (tendon) organs

at junction of tendon and muscle

Joint kinesthetic receptors - within/around synovial joints

1. olfactory cells - bipolar neurons in epithelium

2. olfactory glands - secrete mucus to clean epithelium

3. olfactory nerve (I) - axons of olfactory cells

4. olfactory bulbs - brain region where (I) synapses

5. olfactory tract - axons from bulbs to cortex

1. gustatory cells - neuron with hairlike extension

2. taste buds - location of gustatory cells

3. facial nerve (VII) - anterior 2/3 of tongue

4. glossopharyngeal nerve (IX) - posterior 1/3

5. vagus nerve (X) - throat and epiglottis

6. -> medulla -> thalamus -> cortex

a. eyebrows

b. eyelids (palpebrae)

i. levator palpebrae superioris muscle

ii. palpebral fissure

iii. lateral commissure

iv. medial commissure

v. lacrimal caruncle (lacrimal gland) crying

c. tarsal plate - inner wall of eyelid

d. tarsal glands - secrete oil

e. conjunctiva - mucous membrane of eyelid

f. eyelashes

g. lacrimal gland - for tear secretion

i. lacrimal ducts

ii. lacrimal puncta

iii. lacrimal sac

iv. nasolacrimal duct

a. fibrous tunic - outer coat of the eyeball

i. sclera - posterior portion ii. cornea - anterior portion

b. vascular tunic (uvea) - middle layer

i. choroid - posterior, pigment/vasculature

ii. ciliary body - muscle shapes lens

iii. iris - colored part, with pupil (hole)

c. nervous tunic (retina) - posterior surface

i. photoreceptors (rods & cones)

ii. bipolar cells

iii. ganglion cells

d. lens - just behind pupil and iris

a. photoreceptors pick up the light

b. ganglion cells converge signals -> optic nerve

c. optic nerve -> lateral geniculate of thalamus

d. lateral geniculate -> occipital cortex

a. pinna (auricle) - Ross Perot

b. helix - rim of the pinna c. lobule - your mate's favorite part

d. external auditory canal

e. ceruminous glands - love that earwax!

f. tympanic membrane (eardrum)

a. tympanic antrum - chamber to air cells

b. auditory (Eustachian) tube - to nasopharynx

c. auditory ossicles - bones of middle ear

i. malleus - attached to tympanic membrane

ii. incus - intermediate bone iii. stapes - stirrup

d. tensor tympani muscles - to malleus (protect)

e. stapedius muscle - to stapes (protect)

f. oval and round windows - to inner ear

a. bony labyrinth - has fluid called perilymph

i. vestibule

ii. cochlea

iii. semicircular canals

b. membranous labyrinth - has endolymph

c. vestibule - oval central portion body labyr.

i. utricle & saccule - two sacs

d. cochlea - sound organ, sounds are sensed here

e. semicircular canals - equilibrium in 3-D