Anatomy Unit 1 Test

Gray Matter

• Contains non-myelinated fibers, cell bodies.

• Inner region of the spinal cord (butterfly-shaped).

• Outer region of brain.

White Matter

• Contains myelinated axons.

• Actual shiny, white appearance.

• Inner region of the brain.

• Outer region of the spinal cord.

Meninges

• The brain and spinal cord are wrapped in protective membranes

• 3 Layers:

  • Dura Mater

  • Arachnoid Mater

  • Pia Mater

Dura Mater

• Outer layer.

• White, tough, fibrous connective tissue.

• Inside the skull, the dura mater has 2 layers fused together.

  • Superficial layer adheres to the skull.

  • In some places, the layers separate and form dural venous sinuses.

    • Collects venous blood and excess CSF and returns both to the cardiovascular system.

Arachnoid Mater

• Middle layer.

• “Spider-web” like connective tissue.

• No space between dura.

• Adheres via thin strands to the deeper layer.

Pia Mater

• Deepest meninx.

• Directly attaches to brain/spinal cord.

• Space between arachnoid and pia mater is filled with CSF.

Cerebrospinal Fluid (CSF)

• Clear tissue fluid.

• Protective cushion within and around CNS.

• Formed from blood plasma.

  • Lower protein, glucose, and pH.

• Formed by the choroid plexus in the ventricles.

  • Hollow, interconnecting cavities in the brain.

  • CSF fills the ventricles and the central canal of the spinal cord.

  • Can build up in babies and cause hydrocephalus.

    • “water in the brain.”

1. Gray matter: posterior (dorsal) horn

2. Lateral horn

3. Anterior (ventral) horn

4. White matter: posterior (dorsal) columns

5. Lateral columns

6. Central canal

7. Anterior (ventral) columns

1. Scalp

2. Skull

3. Dura Mater

4. Arachnoid Mater

5. Pia Mater

6. Cerebral Cortex

Cerebrum

General Function: receives sensory input, processes, and commands a response.

• Communicates with and coordinates activities in other parts of the brain.

• Carries out higher thought processes: memory, learning, and language.

General Structure:

• 2 cerebral hemispheres:

  • Separated by longitudinal fissure.

• Connected by a bridge called the corpus callosum.

• Ridges and shallow groves.

  • Gyri (bump) and sulci (groove)

• Divided into 4 lobes: Frontal, parietal, occipital, and temporal.

Cerebral Cortex

• Thin, highly convoluted layer of gray matter.

• Covers each hemisphere.

• Contains over 1 billion cell bodies.

• Processes sensation, voluntary movement, and consciousness.

Cerebellum

• Consists of 2 cerebellar hemispheres.

• Coordinates muscle movements to create smooth motion.

• Regulates posture and balance.

Brain Stem

Midbrain:

• Help cerebellum coordinate muscle movement, movement of eyes, neck and head in response to visual stimuli, startle reflex.

Pons (means bridge):

• Controls breathing and acts as a relay site.

Medulla Oblongata:

• Controls breathing, heart rate, and blood pressure.

• Swallowing, vomiting, coughing, hiccuping, and sneezing.

Production and processing of language.

Broca’s Area

Monitors and regulates motor behavior or movements, including posture, balance and coordination.

Cerebellum

Controls autonomic nervous system and the pituitary gland, hunger, thirst, sleep, and body temperature.

Hypothalamus

Controls emotions, pleasure, and anger.

Limbic System

Relays motor and sensory impulses from the spinal cord to the brain, alertness, awareness, consciousness, and arousal.

Medulla Oblongata

Secretes hormone melatonin.

Pineal Gland

Vision

Occipital lobe

Hearing

Temporal Lobe

Relays info to the cerebral cortex, perception of touch, pressure, and pain.

Thalamus

Amygdala function and associated problems

Functions:

• learning

• fear-processing

• emotion processing

• fight-or-flight response

• reward-processing

Problems:

• disruption of short-term memory

• deficits in recognizing emotions

• irritability

• loss of control of emotion

• aggression

Brain Stem function and associated problems

Functions:

• maintaining homeostasis by controlling autonomic functions

• alertness

• sleep

• balance

• startle response

Problems:

• organ failure

• sleep disorders

• difficulties balancing and moving

Cerebellum function and associated problems

Functions:

• coordination of voluntary movement

• motor-learning

• balance

• reflex memory

• posture

• timing

• sequence learning

Problems:

• loss of fine coordination

• inability to walk

• tremor

• slurred speech

• dizziness

Corpus Callosum function and associated problems

Functions:

• allows info to move between hemispheres and is therefore a very important integrative structure.

Problems:

• schizophrenia

• psychotic episodes

• alzheimer’s

• children w/ ADHD

• non-cognitive disorders

Frontal Lobe function and associated problems

Functions:

• “higher” cognitive functions like executive processes, voluntary control, cognition, intelligence, attention, and language processing.

Problems:

• paralysis

• loss of spontaneity in social interactions

• mood changes

• inability to express language

• atypical social skills and personality traits

Hypothalamus function and associated problems

Functions:

• hunger

• circadian rhythms

• body temperature

• blood pressure and heart rate

• sexual activity

• sleep

Problems:

• weight gain/loss

• hypersomnia

• hypothermia

• chronic stress

• over/under active sex drive

• lethargy

Occipital lobe function and associated problems

Functions:

• vision

Problems:

• hallucinations

• blindness

• inability to see color, motion, or orientation

Parietal lobe function and associated problems

Functions:

• Integrating info from different senses to build a coherent picture of the world.

Problems:

• Inability to attend to people, objects, or one’s own body on the side opposite the damaged area.

Pons function and associated problems

Functions:

• regulates breathing, taste, and autonomic functions

Problems:

• screaming, thrashing arms, punching, and kicking during violent and vivid dreams

Temporal Lobe function and associated problems

Functions:

• perception

• face recognition

• object recognition

• memory acquisition

• understanding language

• emotional reactions

Problems:

• difficulties in understanding speech, faces, and objects

• inability to attend to sensory input

• persistent talking

• long and short-term memory loss

• increased/decreased interest in sexual behavior

• aggression

Thalamus function and associated problems

Functions:

• relaying motor and sensory information

• memory

• alertness

• consciousness

• contributes to perception and cognition

Problems:

• impaired processing of sensory info

• impaired movements and posture

• amnesia

• dementia

• loss of alertness and activation

• sleepiness

• inattention

• coma

• difficulty speaking

• apathy

• pain

Ventricles function and associated problems

Functions:

• cushions and protects the brain

Problems:

• schizophrenia

• bipolar disorder

• dementia

Taste Buds

• Sensory receptors are embedded in taste buds.

• Found mainly in the epithelium of the tongue.

  • Along the raised papillae.

  • Others on the hard palate (roof), pharynx, and epiglottis.

• 5 primary taste sensations.

  • Sweet, sour, salty, bitter, umami.

  • Scattered throughout the tongue.

How the brain receives taste information

• Each taste bud opens at a taste pore.

• Microvilli of taste cells project through taste pore.

• Microvilli have receptor proteins for molecules that allow the brain to distinguish between 5 tastes.

• When molecules bind to the proteins, a nerve signal is sent to the brain (gustatory regions).

Olfactory Cells

• In the epithelium of the nasal cavity.

• Modified neurons.

• Ends with 5 olfactory cilia.

• Contains protein receptors for odor molecules.

How the brain perceives odor

• Each olfactory cell has only 1 type of 1000+ different protein receptors.

• Nerve fibers travel to the olfactory bulb (cranial nerve).

• Multiple signals combined to create the smell signature.

  • Example: a certain food may contain multiple odor molecules that combine.

• Connect directly with the limbic system.

  • Memory and emotion centers.

1. Auricle/Pinna

2. Auditory canal

3. Tympanic membrane

4. Malleus

5. Incus

6. Stapes

7. Oval window

8. Semicircular canals

9. Cochlea

10. Auditory nerve

11. Eustachian tube

Outer ear

• Pinna: outer flap made of skin, cartilage (auricle).

• Auditory canal

  • Passes through the temporal bone.

  • Opening lined with fine hairs and sweat glands.

  • Upper wall contains modified sweat glands.

    • Secrete cerumen or wax.

    • Guard against foreign materials like dust or air pollutants.

Middle Ear

• Tympanic membrane

  • Eardrum.

  • Sound waves hit the membrane and vibrate.

  • Vibrations passed to each ossicle.

• Auditory ossicles

  • Malleus (hammer)

  • Incus (anvil)

  • Stapes (stirrup)

  • Vibration increases 20x as it moves from bone to bone.

• Oval window

  • Small membrane-covered opening in the bone of the inner ear.

  • Passes vibrations to the inner ear.

• Auditory tube (Eustachian tube)

  • Connects to the nasopharynx and equalizes air pressure.

Inner ear

• Found in the bony labyrinth.

  • Carved cavity in the temporal bone.

  • Lined with the membranous labyrinth.

  • Contains 2 fluids:

    • Perilymph and Endolymph.

• 3 areas:

  • Semicircular canals → balance

  • Vestibule → balance

  • Cochlea → hearing

Sound Pathway

1. Through the auditory canal and middle ear.

2. From cochlea to auditory cortex.

• Contains 3 ducts.

  • Vestibular and tympanic duct filled with perilymph.

  • Cochlear duct filled with endolymph.

• Spiral organ - sense organ for hearing.

  • Organ of Corti.

  • Contains tiny hair cells in the basilar membrane.

  • Above is the tectorial membrane connected to nerves.

• When the oval window vibrates.

  • Pressure waves travel through ducts.

  • Basilar membrane moves up and down.

  • Hairs affect signals to the auditory nerve → brain.

Orange - Frontal lobe

Red - Motor cortex

Yellow - Temporal lobe

Blue - Somatosensory cortex

Purple - Parietal lobe

Peach - Occipital lobe

Green - Wernicke’s area

Pink - Broca’s area

White - Cerebellum

B - Cerebellum

C - Thalamus

D - Midbrain

E - Pons

F - Medulla Oblongata

G - Hypothalamus

H - Corpus Callosum

Black circle - Pituitary gland

Black dots - Ventricles

Red dots - Spinal cord

i - Pituitary gland

Olfactory bulb/tract

Optic nerve