Lecture Exam #4

parts of the retina

parts of the retina

macula, fovea, optic nerve, photoreceptors

macula

Dark yellow-orange area with indistinct edges in the retina. It contains the fovea.

fovea

the center of the retina, where cones are densely packed

optic disc

Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light.

rods and cones

photoreceptors in retina

parts of spinal cord

cervical, thoracic, lumbar, sacral,

cervical

neck region

thoracic

chest region with ribs

lumbar

lower back

sacral

area between hips

Structural classification of neurons

multipolar, bipolar, unipolar, anaxonic

multipolar neurons

many dendrites, one axon (most common type)

Bipolar Neurons

one dendrite and one axon

Unipolar neurons

one process extends from cell body

anaxonic neuron

have dendrites but no axons

Functional classifications of neurons

sensory, motor, interneurons

Sensory neurons

• Conduct input from somatic and visceral receptors to CNS

• Most are unipolar (a few bipolar)

Motor neurons

• Conduct output from CNS to somatic and visceral effectors

• All are multipolar

interneurons

• Receive, process, and integrate information from many other neurons

• Generally are multipolar

different parts of a neuron

cell body (soma), dendrites, axon, cytoskeleton

Cell body (soma)

contains nucleus

Dendrites

Branchlike parts of a neuron that are specialized to receive information.

Axon

Long process emanating from cell body

• Makes contact with other neurons, muscle cells, or glands

Cytoskeleton

Composed of microfilaments, intermediate filaments, microtubules

Types of glial cells in Central Nervous System:

astrocytes, microglia, ependymal cells, oligodendrocytes

Astrocytes (star-shaped cells) (CNS)

• Help form blood-brain barrier

• regulate tissue fluid composition

• form structural support, assist neuronal development

• alter synaptic activity (add, eliminate, influence)

• Occupy the space of dying neurons

Ependymal cells (CNS)

• line cavities in brain and spinal cord

• part of choroid plexus which produces cerebrospinal

Microglia (CNS)

• Small cells that wander central nervous system and replicate in infection

• engulf infectious agents and remove debris

Oligodendrocytes (CNS)

Extensions wrap around axons of neurons forming myelin sheath

Glial Cells of the Peripheral Nervous System

satellite cells and neurolemmocytes cells (schwann)

Satellite Cells (PNS)

Electrically insulate and regulate the exchange of nutrients and wastes

Neurolemmocytes (Schwann cells) (PNS)

allows for faster action potential propagation

Lobes of the brain

frontal, parietal, occipital, temporal, insula

frontal lobe function

Motor control, concentration, verbal communication, decision making, planning, personality

parietal lobe function

sensory (sensation)

temporal lobe function

hearing and smell

occipital lobe

vision and visual memories

Insula

memory and sense of taste

parts of diencephalon

thalamus, hypothalamus, epithalamus

Epithalamus function

pineal gland: secretes melatonin and helps regulate day-night cycles Habenular Nuclei: Help relay signals from limbic system to midbrain, Involved in visceral and emotional responses to odors

pineal gland

secretes melatonin

Habenular Nuclei function

Help relay signals from limbic system to midbrain, Involved in visceral and emotional responses to odors

thalamus

Receives signals from all conscious senses except olfaction

Hypothalamus

Control of autonomic nervous system, Control of endocrine system, Regulation of body temperature, Food and Water intake, Sleep-wake rhythms, Emotional behavior

Sclera

white of the eye

iris

Colored part of the eye

pupil

opening in the center of the iris (black part)

retina function

receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition

ciliary muscles function

Changes the shape of the lens to focus light into the retina

aqueous humor

fluid in front of the eye, found between the cornea and the lens

vitreous humor

jellylike substance found behind the lens in the posterior cavity of the eye that maintains its shape

sclera function

helps maintain your eyeball's shape and protects it from injury.

iris function

helps regulate the amount of light entering the eye.

pupil function

let's light into your eye as the muscles of your iris change its shape.

retina function

capture light that comes through the eye and change that light into an electrical signal that your brain interprets as an image.

optic nerve function

sends visual information from the retina to the vision centers of the brain.

ciliary muscle function

alters the shape of the lens with contraction and relaxation

aqueous humor function

Helps the cornea keep its rounded shape, supplies nutrition to the eye

vitreous humor function

let's light pass through while helping eye keep its shape and absorb shock

components of a reflex arc

1. receptor

2. sensory neuron

3. integration center

4. motor neuron

5. effector

5 steps of reflex arc

1. stimulus activates receptor

2. Nerve signal is propagated through sensory neuron to the spinal cord

3. Nerve signal is processed in the integration center by interneurons

4. Nerve signal is propagated by motor neuron to effector

5. Effector responds

brachial plexus

network of interlacing nerves found in the upper arm area

brachial plexus nerves

axillary, musculocutaneous, median, ulnar, radial

cervical plexuses

innervate the neck and sections of the head, chest, and shoulders and the diaphragm

cervical plexuses nerves

phrenic nerve

Lumbar plexuses nerves

femoral and obturator nerves

how to do a lumbar puncture/spinal tap

• Needle passes through Skin, back muscles, ligamentum flavum

• Lie on your side with your knees drawn up to your chest. Then a needle is inserted into your spinal canal — in your lower back — to collect cerebrospinal fluid for testing

difference between saltatory and continuous nerve conduction.

Saltatory conduction is much faster than continuous conduction and myelinated cells use less ATP to maintain resting membrane potential

continuous nerve conduction

unmyelinated axons where conduction is slower.

Saltatory nerve conduction

occurs on myelinated axons

optic nerve

the nerve that carries neural impulses from the eye to the brain

step 1 of reflex arc

1. stimulus activates receptor

step 2 of reflex arc

2. Nerve signal is propagated through sensory neuron to the spinal cord

step 3 of reflex arc

3. Nerve signal is processed in the integration center by interneurons

step 4 of reflex arc

4. Nerve signal is propagated by motor neuron to effector

step 5 of reflex arc

5. Effector responds

cervical plexuses

innervate the neck and sections of the head, chest, and shoulders and the diaphragm

cervical plexuses nerves

phrenic nerve

Lumbar plexuses

Innervates abdominal wall muscles, anterior and medial thigh

Lumbar plexuses nerves

femoral and obturator nerves

how to do a lumbar puncture/spinal tap

Needle passes through Skin, back muscles, ligamentum flavum

difference between saltatory and continuous nerve conduction

Saltatory conduction is much FASTER than continuous conduction and myelinated cells use less ATP to maintain resting membrane potential

continuous nerve conduction

unmyelinated axons where conduction is slower.

Saltatory nerve conduction

occurs on myelinated axons

rods and cones

optic nerve

transmits electrical impulses from your eyes to your brain

optic disk

Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light.

eardrum

tightly stretched membrane located at the end of the ear canal that vibrates when struck by sound waves

external auditory meatus

ear hole

ear canal

a tube running from the outer ear to the middle ear

incus

a small hammer-shaped bone in the middle ear, transmitting vibrations between the malleus and stapes.

malleus

a small bone in the middle ear which transmits vibrations of the eardrum to the incus. (thing in middle)

stapes

involved in the conduction of sound vibrations to the inner ear.

cochlea

snail-shaped structure of the inner ear that is filled with fluid

semicircular canals

Fluid filled canals in the inner ear responsible for our sense of balance.

anterior chamber of eye

between cornea and iris

posterior chamber of eye

between iris and lens

conjunctiva

Delicate membrane lining the eyelids and covering the eyeball

cornea

the transparent layer forming the front of the eye.

choroid

middle, vascular layer of the eye, between the retina and the sclera