Nakamura Human Physiology Lecture 3

Question 1

Central Nervous System

Answer 1

.Consists of:
    –Brain
    –Spinal cord
•Major regions of adult brain are:
      –Cerebrum
      –Brain Stem
      –Cerebellum
•Surface Features:
     –“Bumps” are gyri
     –“Grooves” are sulci
•CNS covered by meninges(connective tissue)
Protection: meninges, cerebral spinal fluid, skull

Question 2

Telencephalon

Answer 2

.•Cerebrum (cerebral cortex if referring to surface) is largest portion of brain. Responsible for higher brain functions.
•Has 5 lobes:
➢Frontal Lobe
➢Parietal Lobe
➢Temporal Lobe
➢Occipital Lobe
➢Insula- deep within the lateral sulcus (linked to emotion or the regulation of the body’s homeostasis)

Question 3

Frontal lobe

Answer 3

.Precentral gyri-Involved in motor control.
Motor homonculous
•Body regions with the greatest motor innervation occupy the largest areas of motor cortex.

Question 4

Frontal lobe and personality

Answer 4

.Skull of Phineas Gage (railway foreman–1848)
•Tamping rod through the frontal lobe
•Before accident he was likeable and friendly
•After accident he was irritable and mean

Question 5

Parietal lobe

Answer 5

.•Post central gyri- Responsible for perception of somatesthetic sensation.
Sensory homonculous
•Body regions with highest densities of receptors occupy the largest areas of sensory cortex

Question 6

MRI of sensory cortex

Answer 6

-stimulate different area and see which areas of the brain light up
-Magnetic Resonance Imaging (MRI)
•Protons (H+) respond to a magnetic field
-Electroencephalogram (EEG)
* Measure “synaptic potential” -> “electrical currents

Question 7

Temporal lobe

Answer 7

-Interpretation of auditory centers that receive sensory fibers from cochlea (inner ear).
–Interpretation and association of auditory and visual information.

Question 8

Occipital lobe

Answer 8

,Primary area responsible for vision and coordination of eye movements.

Question 9

Diencephalon

Answer 9

.Major components:
–Thalamus
–Hypothalamus (endocrine system boss)
–Pituitary gland
–Pineal gland (melatonin sleep wake cycle)

Question 10

Thalamus

Answer 10

.Composes the majority of the diencephalon.
•Acts as relay center for all sensory information (except olfactory) to the cerebrum (ascending pathway: sensory to center)
–Lateral geniculate nuclei (LGN) or Lateral geniculate body (LGB) relay visual information before occipital lobe
–Medial geniculate nuclei (MGN or MGB) relay auditory information before temporal lobe

Question 11

Midbrain

Answer 11

.•Contains:
–Corpora quadrigemina
–Cerebral peduncles
–*Substantia nigra*
–Red nucleus
•Functions:
–Visual reflexes.
–Relay center for auditory information.
–Motor coordination: Degeneration of axon fibers from substantia nigra causes Parkinson’s disease(can't make enough dopamine)

Question 12

Hindbrain

Answer 12

•Metencephalon:
–Pons:
•Contains respiratory centers
–Cerebellum:
•Receives input from proprioceptors (located in big joints, keep body stable)
•Coordination of movement.
•Myelencephalon (medulla):
–All descending and ascending fiber tracts between spinal cord and brain must pass through the medulla.
–Cardiac control center:
•Regulates autonomic nerve control of heart.
–Regulates respiration with the pons

Question 13

Ascending spinal tracts

Answer 13

• cross. Left goes to right and right goes to left

- Convey sensory information from cutaneous receptors, proprioceptors and visceral receptors to cerebral cortex.

Question 14

Descending spinal tracts

Answer 14

.Pyramidal tracts descend directly without synaptic interruption from cerebral cortex to spinal cord.
–Fine movements.
•Reticulospinal tracts (extrapyramidal):
–Gross motor movement.

Question 15

Cerebral later alizarin

Answer 15

.Specialization of one hemisphere.
•Left hemisphere:
–More adept in language and analytical abilities.
-right hand
-speech, writing, calculation
•Right hemisphere:
–Limited verbal ability.
–Most adept at visual/spatial tasks.
-left hand
Commissure allows communication between the two

Question 16

Broca’s area

Answer 16

Frontal lobe
-Involves articulation of speech.
–After damage to Broca’s area, comprehension of speech is unimpaired.
-Can understand a sentence but have difficulty repeating it.
-Motor speech area

Question 17

Wernicke’s area

Answer 17

-parietal lobe
-Involves language comprehension.
–In damage to Wernicke’s area, language comprehension is destroyed, but can still speak.
-Speech is rapid but has no meaning.

Question 18

Nervous system overview

Answer 18

CNS (central nervous system):
   –Brain
   –Spinal cord
•PNS (peripheral nervous system):
   –Cranial nerves
   –Spinal nerves
•2 Types of cells in nervous system:
   –Neurons
   –Supporting cells (neuroglia or glial cells)

Question 19

Neurons

Answer 19

-Structural and functional units of the nervous system
•Respond to physical and chemical stimuli
•Produce and conduct electrical impulses (action potential)
•Release chemical transmitters (neurotransmitters) at synapse

Question 20

Neuron structure

Answer 20

.Cell body (perikaryon)
–Contains the nucleus, and other organelles
–Provides receptive area
•Dendrites
–Provide receptive area
–Conducts electrical activity toward cell body
•Axon (nerve fiber)
–Actively conducts electrical impulses away from cell body.