Lecture 7 (Brain)

Question 1

What is the Central Nervous System composed of? What are its main functions?

Answer 1

• Made up of the brain and spinal cord
• Principal integrator of the sensory input and motor output
• Evaluates incoming stimuli (information)
• Formulates responses to changes that threaten homeostasis

Question 2

What are the 2 coverings of the Brain and Spinal Cord?

Answer 2

1) Bones

2) The inner coverings = The meninges

Question 3

What is the meninges that protect the brain called?

Answer 3

Cranial Meninges

Question 4

What are the 3 layers of the meninges called? Describe each of them.

Answer 4

1) Dura mater : outermost layer, tough dense connective tissue

2) Arachnoid mater : middle layer, made of collagen and elastic fibers (looks like spider web)

3) Pia mater : inner layer, transparent layer of collagen and elastic fiber that sticks to surface of spinal cord, contains numerous blood vessels, situated between arachnoid and pia mater (subarachnoid space = where cerebrospinal fluid circulates)

Question 5

What is meningitis? What is it caused by?

Answer 5

• Inflammation of the meninges
• Caused by bacterial or viral infections
• Can be fatal if untreated

Question 6

What are the functions of the coverings of the Central Nervous System?

Answer 6

• Provides a supportive and protective cushion
• Reservoir of circulating fluid that monitors internal environment
• Travels around the brain and the spinal cord
• Travels within the 4 large ventricles of the brain

Question 7

What is the main component of the CNS?

Answer 7

The Brain

Question 8

Name the 4 major parts of the brain

Answer 8

• The Brain Stem
• Diencephalon
• Cerebellum
• Cerebrum (Cortex)

Question 9

What’s the difference between white mater and grey mater?

Answer 9

White mater : myelinated axons, sending signals, found deeper in the brain

Grey mater : cell bodies, neuroglia, unmyelinated axons, process signals, found in outer surface of braon

Question 10

What is the Brain Stem? Where is it situated?

Answer 10

The part of the brain between the spinal cord and diencephalon.

Question 11

What are 3 parts of the Brain Stem? Where are they situated?

Answer 11

• Medulla Oblongata (bottom)
• Pons (middle)
• Midbrain (top)

Question 12

Describe the Medulla Oblongata

Answer 12

Controls the basic life support systems
- Cardiovascular centre = regulates heart rate and blood presuure

• Medullary rhythmicity area = adjusts breathing rate
• Reflex integration center = swallowing, vomiting, coughing, sneezing

Question 13

Describe the Pons

Answer 13

The pons is a bridge that connects parts of the brain with one another

• Relays information from one side of cerebellum to other
• Relays information up to cerebrum
• Helps control breathing, sleeping, swallowing…

Question 14

Describe the Midbrain

Answer 14

Connects the pons to the diencephalon.

• Coordinates muscle movement
• Involved with reflexes that control eye movement (visual tracking)
• Center for the “startle reflex”

Question 15

What are the 3 main regions of the diencephalon?

Answer 15

1) Thalamus
2) Hypothalamus
3) Pineal Gland

Question 16

Visualize where the thalamus is situated. What is its main function?

Answer 16

Major relay for most sensory impulses from spinal cord to cerebral cortex.
Plays a role in maintenance of consciousness.

Question 17

Visualize where the Hypothalamus is situated? What is its main function?

Answer 17

• Controls the pituitary glands (Releasing hormones) and produces hormones (oxytocin and ADH)
• Primary connection between nervous system and endocrine system
• Controls the autonomic nervous system = contraction of smooth and cardiac muscle
• Regulates emotional and behaviour patterns
• Regulates eating and drinking behaviour (contains thirst centre)

Question 18

Visualize where the Pineal Gland is situated? What is its main function?

Answer 18

The body’s biological clock depends partly on the pineal gland by varying the secretion of melatonin

Question 19

Where is the cerebellum located?

Answer 19

Located posterior to the midbrain and inferior to the cerebrum.

Question 20

What are the functions of the Cerebellum?

Answer 20

• Receives sensory input from muscles, joints, tendons
• Compares actual movements with intended ones
• Helps produce smooth, coordinated movements
• Help execute skilled motor activities
• Maintains posture and balance

Question 21

Define Ataxia (Happening in Cerebellum)

Answer 21

Disrupted muscle coordination
Caused by damage to cerebellum or even alcohol

Question 22

Describe the cerebrum. Where is it situated?

Answer 22

Area of higher brain function (reading, writing, speaking, memories, future plans)

• Outer layer : Cerebral cortex (gray mater)
• Inner layer : white mater
• Surface folds of cerebral cortex : gyri
• Groves between gyri : sulci
• Deep grooves = Fissures
• Longitudinal fissure: divides cerebrum into right and left hemispheres
• Hemispheres are connected by corpus callosum

Question 23

What are the 4 lobes found in each cerebral hemisphere?

Answer 23

• Frontal
• Occipital
• Parietal
• Temporal

Question 24

What are the 3 types of functional areas in the lobes?

Answer 24

1) Sensory=receive sensory input (involved in perception of senses)

2) Motor areas=initiation of movement

3) Association areas=integration of information

Question 25

What are the characteristics of the Frontal lobe?

Answer 25

Primarily motor functions and association areas 1) Primary motor area (motor) - Control of muscle contraction - Right side controls left side of body 2) Broca's speech area (motor) - Muscle control speech (language) 3) Premotor area (association) - Prepares sequences of complex muscle contractions

Question 26

What is the main characteristic of the Occipital lobe?

Answer 26

1) Primary visual area (sensory) - Responsible for visual perception

Question 27

What are the main characteristics of the Parietal lobe?

Answer 27

Sensory function and has association areas. 1) Primary somatosensory area (sensory) - receives sensory input (tactile, T°, pain, itching, tickling) 2) Primary gustatory area (sensory) - Taste 3) Wernicke's area (association) - Responsible for interpretation of speech 4) Common integration area (association)

Question 28

What are the characteristics of the Temporal lobe?

Answer 28

1) Primary auditory area (sensory): - responsible for sound and perception of what is heard 2) Primary olfactory area (sensory): - receives signals relating to smell and perception of smell 3) Auditory association area (association): - interpretation of sound 4) Wernicke's area(association): - also found overlapping into temporal lobe - responsible for interpretation of speech

Question 29

What's the Limbic system?

Answer 29

Consists of a ring of structures on inner border of cerebrum and floor of diencephalon Called "emotional brain" = plays primary role in pain, pleasure, anger, affection and behaviour Key function in memory development

Question 30

Define Hemispheric lateralization. What is the left side more important for? What is the right side more important for?

Answer 30

The hemispheres of the brain have some small differences, both in anatomy and function Left side: Language, logic, math, science Right side: Artistic skills, music, spatial and pattern perception