a&p practial 3 functions

Neuron cell body

Houses nucleus and organelles; integrates signals from dendrites.

Axon

Transmits electrical impulses (action potentials) away from the cell body

Dendrite

Receives incoming signals from other neurons

Myelinated nerve fibers

Increase the speed of signal conduction

Myelin sheath

Insulating layer that speeds up electrical impulses

Node of Ranvier

Gaps in myelin; enable saltatory conduction of action potentials

Schwann cells

Produce myelin in the PNS; support axonal regeneration

Unipolar neuron

Sensory; cell body off to the side; conducts impulses toward CNS.

Bipolar neuron

Sensory; one dendrite and one axon; specialized for sensory organs

Multipolar neuron

Motor or interneurons; multiple dendrites, one axon

Endoneurium

 Surrounds individual nerve fibers

Perineurium

Surrounds bundles of nerve fibers

Epineurium

Outermost layer; encloses entire nerve

Dura mater

Tough outer layer; protects CNS

Arachnoid mater

facilitates CSF circulation and acts as a barrier to substances entering the CSF

Pia mater

helps contain CSF

Frontal lobe

Voluntary movement, reasoning, planning, speech, emotion

Parietal lobe

Sensory input, spatial processing

Occipital lobe

Visual processing

Temporal lobe

Auditory processing, memory, language

Arbor vitae

White matter of cerebellum; coordinates motor signals

Dural sinuses

 Superior sagittal sinus: Drains venous blood from brain

Subdural space

 Between dura and arachnoid; potential space for hematomas

Subarachnoid space

Contains CSF; cushions brain

Longitudinal fissure

Divides the left and right cerebral hemispheres

Olfactory bulb (I)

Receives smell input

Olfactory tract

Carries smell signals to brain

Optic (II) nerve

Transmits visual info from retina

Optic chiasma

 Crossover of optic nerve fibers

Optic tract

Carries visual signals to thalamus

Pituitary gland

Endocrine gland; regulates hormones

Mammillary body

Involved in memory processing

Midbrain

Visual & auditory reflexes, motor control

Cerebral peduncles

Motor tracts from cortex to pons/spinal cord

Oculomotor (III) nerve

Eye movement, pupil constriction

Pons

Relay between cortex & cerebellum; controls breathing

Trigeminal (V) nerve

Facial sensation and chewing

Medulla oblongata

 Controls heart rate, breathing, reflexes

Superior colliculi

 Visual reflexes

Inferior colliculi

 Auditory reflexes

Pineal gland

Secretes melatonin; regulates sleep

Corpus callosum

Connects hemispheres

Fornix

Connects hippocampus to hypothalamus

Hypothalamus

Homeostasis; controls pituitary

Thalamus

Relay center for sensory signals

Lateral ventricle

Holds CSF

Septum pellucidum

Thin membrane between lateral ventricles

Third ventricle

produce or secrete CSF

Fourth ventricle

produce, drain, and circulate CSF

Cerebral aqueduct

Connects 3rd and 4th ventricles

Choroid plexus

Produces CSF

I Olfactory

Smell

II Optic

Vision

III Oculomotor

Pupil constriction

IV Trochlear

eye movement

V Trigeminal

facial sensation, chewing

VI Abducens

eye movement

VII Facial

Facial expression, taste

VIII Vestibulocochlear

Hearing, balance

IX Glossopharyngeal

Taste, swallowing

X Vagus

Parasympathetic control, visceral sensation

XI Accessory

Head, neck, shoulder movement

XII Hypoglossal

Tongue movement

Meninges of spinal cord

Same 3 layers as brain

Epidural space

Fat-filled space outside dura; site of epidural anesthesia

Posterior/dorsal funiculi

Fine touch, vibration, proprioception

Lateral funiculi

Motor tracts

Anterior/ventral funiculi

Mixed motor/sensory tracts

Anterior median fissure

Deep groove on front side of cord

Posterior median fissure

Shallow groove on back side

Dorsal horns

Sensory processing

Ventral horns

Motor neuron cell bodies

Lateral horns

Autonomic neurons

Central canal

Carries CSF

Gray commissure

Connects gray matter halves

Dorsal root

Carries sensory info to spinal cord

Dorsal root ganglia

Sensory neuron cell bodies

Ventral root

Carries motor info away from spinal cord

Eyelashes/eyelid

Protection from debris and light

Conjunctiva

Lubricates eye; lines eyelid and sclera

Extrinsic eye muscles

Move the eyeball

Sclera

 White of eye; maintains shape

Cornea

Transparent; refracts light

Iris

Regulates pupil size

Pupil

Opening for light entry

Ciliary Body

Produces aqueous humor; changes lens shape

Ciliary muscles

Control lens shape for focus

Ciliary process

Produces aqueous humor

Choroid

Nourishes retina; pigment absorbs stray light

Lens

Focuses light on retina

Vitreous Humor

Maintains shape of eyeball

Aqueous Humor

Nourishes cornea/lens; maintains pressure

Optic Disc

No photoreceptors; where optic nerve exits

Macula Lutea

Region of high visual acuity

Fovea Centralis

Center of macula; sharpest vision

Optic Nerve

Carries visual signals to brain

Photoreceptors

 Detect light/color

Bipolar cells

Transmit signals from photoreceptors to ganglion cells

Ganglion cells

Their axons form the optic nerve

Auricle

Collects sound