A&P Unit 4 Lecture Exam

Increase as you age

- neuron size
- # of synapses
- myelin
- # neuralgia

Organization of the Brain

1. Brain stem
2. Diencephalon
3. Cerebrum
4. Cerebellum

Brain stem

Medulla oblongata, pons, midbrain

Brain stem

Control highly programmed, automatic functions needed for survival

Brain stem

Controls heart rate, blood pressure, breathing

Diencephalon

Thalamus, hypothalamus, epithalamus

Cerebrum

Largest area of brain

Cerebrum

Controls most mental and physical activity

Cerebellum

Balance, posture, coordination

All sensory and motor info b/t spinal cord and upper brain regions must pass thru all 3 regions of:

Brain Stem

Medulla Oblongata

Most inferior region of brain stem, joins with spinal cord

Nuclei that control vital functions

Vital centers

Has vital and non-vital centers

Medulla Oblongata

Cardiac center (Vital)

Controls heart rate

Vasomotor center (Vital)

Controls blood pressure

Medullary respiratory center (Vital)

Controls basic respiratory rhythm

Medulla Oblongata non-vital centers control:

Cough, sneeze, vomit, hiccups, swallowing

Motor tracts bundled into triangular shaped structures within Medulla Oblongata

Pyramids

Cranial nerves 9-12 arise from this area of the brain stem

Medulla Oblongata

Major sensory and motor tracts

Medulla Oblongata

Area of brain stem superior to Medulla Oblongata

Pons

Pontine respiratory centers

Controls transition b/t inhale and exhale

Pontine respiratory centers located in this area of brain stem

Pons

Cranial nerves 5-8 arise from this area of brain stem

Pons

Major sensory and motor tracts

Pons

Midbrain

Most superior part of brain stem

Joins thalamus superiorly

Midbrain

Cerebral peduncles

Anterior side of midbrain

Cerebral aqueduct

Tiny canal runs through midbrain, carries CSF from from 3rd to 4th ventricle

Corpora quadrigemina

4 rounded mass of grey matter, posterior to cerebral aqueduct

Superior colliculi

2 superior masses of grey matter

Responsible for visual startle reflexes and involuntary tracking of moving objects with eyes

Superior colliculi

Inferior colliculi

2 inferior masses of grey matter, smaller than superior

Responsible for auditory startle reflexes and is part of hearing pathway

Inferior colliculi

Buried within cerebral peduncles (2 pairs nuclei)

Red nuclei & substantia nigra

Responsible for coordination, decreased unwanted motor function (shaking)

Red nuclei & substantia nigra

Joins midbrain inferiorly

Thalamus

Thalamus

Traffic director for incoming sensory info

All sensory information (except smell) goes here, info sent to appropriate areas of cerebrum for interpretation

Thalamus

Some interpretation of sensation (pleasant/unpleasant)

Thalamus

Area of Diencephalon inferior to thalamus

Hypothalamus

Infundibulum

Connected to pituitary gland by stalk within Hypothalamus

Hypothalamus

“Sexy center of brain”, regulate body temp and day/night cycles, thirst and hunger centers

Primary control of autonomic NS (motor info to heart muscle, smooth muscle, glands)

Hypothalamus

At heart of limbic system (emotional brain), joy, affection, fun (enjoyment) & pleasure, sadness, grief, stress

Hypothalamus

The 3 F’s apply here (food, fun, sex)

Hypothalamus

Habenular nuclei

Visceral & emotional responses to fragrances

Pineal gland

Pine cone shaped gland that secretes the hormone melatonin

Melatonin

Hormone secreted only in darkness
Increase in this hormone increases sleepiness, and decreases happiness and “sexy”

Area of Diencephalon that includes habenular nuclei and pineal glands

Epithalamus

Seasonal affective disorder (SAD)

Seasonal depression
May relate to increased levels of melatonin in winter

Area of brain separated into 2 mirror image hemispheres by longitudinal fissure

Cerebrum

Cerebrum

Separated from cerebellum by transverse fissure

Convolutions

Folds on surface of cerebrum

Gyrus

Ridge
Part of cerebrum

Valley

Grooves on cerebrum

Suicus

Shallow groove on cerebrum

Fissure

Deep groove on cerebrum

Insula lobe of cerebrum hemispheres

Cerebrum folds inward to form this lobe

Cerebral cortex

Outer surface of cerebrum
neuron cell bodies (grey matter)

White matter

Myelinated fibers transmitting info
Under cerebral cortex

Basal (cerebral) nuclei

Other areas of grey matter in cerebrum (not part of cortex), buried in white matter of cerebrum

Cerebral cortex

Outer surface of brain

“Conscious mind”

Cerebral cortex

Cerebral cortex

Controls most sensory and motor function, personality, communication

Motor areas of cerebral cortex

Control voluntary motor function
All in frontal lobe

Sensory areas of cerebral cortex

Receive and interpret incoming sensory info

Association areas of cerebral cortex

Memories, learning, receive info from sensory areas + integrate it, higher brain function

Primary motor cortex (cerebral cortex)

Located on gyrus, anterior to central sulcus (pre central gyrus)

Motor homunculus

Mapping of primary motor cortex

Primary motor cortex

Specific neurons in this area control motor function of specific muscles

Damage of primary motor cortex

Lose motor function of affected area on OPPOSITE side of body

Primary motor cortex

Fine motor control (face, hands)
More neurons controlling muscles in this area
Take up more space

Premotor cortex (cerebral cortex)

anterior to primary motor cortex

Premotor cortex

stores memories of learned muscle activity - muscle memory
(typing, playing an instrument)

Planning center for motor events

Premotor cortex

Damaged Premotor cortex:

lose muscle memory

Broca's Area

motor speech area
coordinates motor movements needed for speaking

Damaged Broca's area:

lose ability to speak

Frontal eye field

control voluntary eye movement

Damaged frontal eye field:

lose ability to voluntarily move eyes

Sensory association areas

- memory banks for sensory events
- store memories of previous sensory events + allow to make associations b/t incoming sensory info and memories
- provide meaning/understand incoming sensory info

Location of Primary Somatosensory Cortex

located on gyrus (ridge) posterior to central sulcus (post central gyrus)

Primary Somatosensory Cortex

receive + interpret incoming somatosensory info s

Somatosensory information

touch, pain, itch, temperature from skin, muscles, bones, joints

Specific neurons on this area receive incoming somatic sensory info from specific body regions

Primary somatosensory cortex

Damaged primary somatosensory cortex:

lose sensation from affected area on OPPOSITE side of body

Somatosensory association center

memory bank for previous somatic sensory events + allows you to make associations b/t incoming sensory info and meaning

Ex: digging in pocket, gives meaning to what you're feeling

Somatosensory association cortex

Damaged somatosensory association cortex:

loss of somatic sensory memory

Primary visual cortex

receive + interpret incoming visual info (color, shape)

Damaged primary visual cortex:

lose vision

Visual association cortex

- memory bank for visual events
- interpret incoming visual info based on memory
(Ex: someone's face)
- meaning to what you see)

Damaged visual association cortex:

No visual memory
- no meaning to what you're seeing

Primary auditory cortex

receive + interpret incoming sound info (volume, pitch, rhythm)

Damaged primary auditory cortex

hearing loss

Auditory association cortex

- memory bank for auditory events
- give meaning to auditory events (voice recognition, singing a song)

Auditory association cortex

make associations b/t incoming auditory info + auditory memories

Damaged auditory association cortex:

lose auditory memory

Primary gustatory cortex

receive + interpret incoming taste info