Physiology Lab Exam 2

How many cranial nerves are there?

12 pairs

Are cranial nerves CNS or PNS?

PNS

olfactory nerve (I)

sensory, smell

optic nerve (II)

sensory, vision

Oculomotor (III)

primarily motor, move the eyes, adjust the amount of light, focus lenses, raise eyelids

Trochlear Nerve (IV)

motor, eye movement

Trigeminal nerve (V)

mixed, Ophthalmic division, Maxillary division, Mandibular division

ophthalmic division

sensory from surface of eyes, tear glands, scalp, forehead, and upper eyelids

maxillary division

sensory from upper teeth, upper gum, upper lip, palate, and skin of face

mandibular division

-sensory from scalp, skin of jaw, lower teeth, lower gum, and lower lip
-motor to muscles of mastication and muscles in floor of mouth

Abducens nerve (VI)

Motor: lateral eye movement

Facial Nerve (VII)

-mixed nerve
-sensory from taste receptors
-motor to muscles of facial expression, tear glands, and salivary glands

Vestibulocochlear nerve (VIII)

sensory, hearing and balance

Vestibular branch

balance, equilibrium

cochlear branch

hearing

Glossopharyngeal nerve (IX)

Mixed nerve
Sensory from pharynx, tonsils, part of tongue
Motor to salivary glands and muscles of pharynx (for swallowing)

vagus nerve (X)

Mixed nerve
Somatic motor to muscles of speech and swallowing
Autonomic motor to heart, other viscera of thorax and abdomen
Sensory from pharynx, larynx, esophagus, and viscera of thorax and abdomen

Accessory nerves (XI)

motor function (neck, upper back)
Cranial branch: motor impulses of the soft palate, pharynx, and larynx
Spinal branch: motor impulses to muscles of the neck and shoulder

Hypoglossal Nerve (XII)

motor: muscles of the tongue

are cranial nerves sensory, motor, or both

both

EEG (electroencephalogram)

§ Recording of electrical activity in the brain, specifically in the cerebral cortex via electrodes placed on the scalp

§ Recording the sum of electrical activity in many thousands of neurons in the cerebral cortex

§ Safe, non invasive, and painless method of recording the sum of electrical activity in many thousands of neurons in the cerebral cortex

what EEG used for

Can be used to assess states of consciousness (awake, concentrating, asleep) and various brain disorders, and to establish brain death

EEG waves

brain waves that you measure in order to measure brain activity during sleep

Types of EEG waves

alpha, beta, theta, delta

beta waves

Lowest amplitudes; dominant during high levels of attentiveness

alpha waves

brain waves that indicate a state of relaxation or light sleep

delta waves

highest amplitudes, occur mainly during the deeper stages of sleep

theta waves

brain waves indicating the early stages of sleep; light sleep

frequency waves

o number of complete wave cycles that occurs each second (Hertz)
§ Indication of the state of alertness; the higher the frequency the more alert and attentive the person is

amplitude of a wave

o brain wave is the height, or magnitude of the wave (microvolts)
§ Indicates the degree of synchrony, or simultaneous firing of many neurons underneath the recording electrodes

bipolar method of recording an EEG

o Two electrodes are placed over the same region of the cerebral cortex, perhaps 2-3 inches apart, and the difference in the electrical potential (voltage) between the electrodes is measure
o A third electrode is placed over the mastoid process as a "ground" or reference point for the body's baseline voltage

Epimysium

surrounds entire muscle

Perimysium

covers bundles of cells (fascicles) within the muscle

Endomysium

surrounds each individual muscle fiber

aponeurosis

strong sheet of connective tissue that acts as a tendon to attach muscles to bone

sarcomere

functional contractile unit within muscle fiber

a band

dark area; extends length of the thick filaments;

I band

light band of thin filaments and bisecting Z disc

H zone

light band in middle of A band

Z disc

thin and elastic filaments anchored at ends of sarcomere

Agonist (prime mover)

Muscle or group responsible for the movement.

Antagonist

o muscle responsible for action in the opposite direction of an agonist or for resistance to an agonist

Synergist

muscle that assists an agonist, often by supplementing the contraction force

Fixator

special type of synergist muscle; muscle contraction will stabilize a joint so another contracting muscle exerts a force on something else

Troponin

regulatory protein that binds to actin, tropomyosin, and calcium

Tropomyosin

A protein of muscle that forms a complex with troponin regulating the interaction of actin and myosin in muscular contraction

myosin

thick filament

actin

thin filaments

organelles involved in muscle contraction

o Each motor neuron associated with skeletal muscle fibers innervates a certain number of fibers
o A single motor neuron plus all of the muscle fibers it controls is called a motor unit
o In a motor unit, whenever the motor neuron is activated, all of its muscle fibers are commanded to contract simultaneously

muscle striations

A striped or striated pattern within myofibrils: alternating dark, thick filaments (A bands) and light, thin filaments (I bands)

temporal summation

o When a single muscle fiber is stimulated by its motor neuron to contract, then relaxes completely, and then contracts again, the subsequent contractions all produce the same amount of muscle tension
o However, if a muscle fiber is stimulated again, before it has time to relax completely, then the second twitch will generate more tension than the first
o Summation it's the body's way of increasing the force generated by muscles

tetanic muscle contraction

o When a muscle fiber is stimulated to contract by several stimuli in rapid succession, and there is no opportunity for muscle relaxation between stimuli, the tension increases until it reaches the maximum possible force for that muscle fiber, and then remains at that level until the stimulation stops

EMG (electromyogram)

o recording of skin-surface voltage that is produced by underlying skeletal muscle contraction
o The voltage procedure by contraction is weak, but it can be picked up by surface sensors to produce the recording (EMG)

Sulcus

shallow groove

central sulcus

divides the frontal from the parietal lobe

Lateral sulcus (fissures)

divides the temporal from the parietal lobe

Parieto-occipital sulcus

divides the occipital from the parietal love

Groove (fissures)

deep grooves

Longitudinal fissure

separates the cerebral hemispheres; contains falx cerebri, a dural septum

Transverse fissure

separates the cerebrum from the cerebellum; contains tentorium cerebellum; a dural septum

Cranial and spinal cord meninges

dura mater, arachnoid mater, pia mater

dura mater

outermost layer, adheres to the inside of the skull

Arachnoid mater

middle layer, weblike, semitransparent, spans the fissures of the brain

Pia mater

innermost, thin delicate and adheres tightly to the surface of the ridges (gyri)

lateral ventricles

the largest ventricles; one located in each cerebral hemisphere

Third ventricle

located within the diencephalon inferior to the corpus callosum

Fourth ventricle

located between the pons and the cerebellum

Gyri

elevated surface ridges
· Precentral gyrus
· Post central gyrus

Lobes of the cerebrum

frontal, parietal, temporal, occipital, insula

Cerebrum

controls higher brain functions. Including sensory perception, storing memory, reasoning, and determining intelligence; initiates voluntary muscle movements

Cerebral cortex

· Thin surface layer of gray matter containing very little myelin; area of conscious awareness and processing information

Cerebral white matter

· Largest portion of the cerebrum containing myelinated nerve fibers; transmits impulses between cerebral areas and lower brain centers

basal nuclei

· Masses of gray matter deep within the white matter; sometimes called basal ganglia as a clinical term; relay motor impulses from the cerebral cortex to the brainstem and spinal cord; the main structures include the caudate nucleus, putamen, and globus pallidus

Thalamus

· largest portion; relay station for sensory impulses ascending from other parts of the nervous system to the cerebral cortex

hypothalamus

· inferior portion; helps maintain homeostasis by regulating visceral activities and by linking the nervous and endocrine systems; regulates body temperature, sleep cycles, emotions and autonomic nervous system control

Optic chiasma (chiasm

optic nerves meet

Mammillary bodies

pair of small humps

Pineal gland

· formed from epithalamus secretes hormone melatonin

Midbrain

· superior region of brainstem; contains visual reflex centers that move the eyes and head and auditory reflex centers; contains fiber tracts that connect the pons with the cerebrum; contains aqueduct between third and fourth ventricles where CSF flows

Cerebral peduncles

connect pons to cerebrum

Corpora quadrigemina

o four bulges (two superior colliculi (visual reflexes) and two inferior colliculi (auditory reflexes))

Cerebral aqueduct

o cerebrospinal fluid flows from third to fourth ventricle

Pons

bulge on underside of brainstem; relays impulses between higher and lower brain regions; helps regulate rate and depth of breathing

Medulla oblongata

inferior region of brainstem; conducts ascending and descending impulses between the brain and spinal cord; contains cardiac, vasomotor, and respiratory control centers and various nonvital reflex control centers

Cerebellum

§ cauliflower-like appearance; processes information from other parts of the CNS by nerve tracts; integrates sensory information concerning the position of body parts; and coordinates muscle activities and maintains posture
· Right and left hemispheres

· Vermis:

connects the two hemispheres

· Cerebellar cortex:

gray matter portion

Arbor vitae:

deeper branching pattern of white matter

Primary somatosensory cortex

sensory, · receives information from skin receptors and proprioceptors

Somatosensory association cortex

· integrates sensory information from primary cortex

Wernicke's area

sensory, process spoken and written language

Visual areas

· consists of a primary and association (interpretation) area for vision

Auditory areas

· consist of a primary and association area for hearing

Olfactory association area

interpretation of odors

Gustatory cortex

perceptions of taste

Primary motor cortex

· controls skeletal muscles

Motor association (premotor) area

planning body movements

Broca's area

planning speech movements (motor)

Endoneurium

o connective tissue around each nerve fiber and the Schwann cell

Perineurium

surrounds bundle of nerve fibers (fascicle)