W1 - Brain structures ✅

Question 1

Directions in the Nervous System

Answer 1

Anterior/Rostral - front
Posterior/Caudal - back
Superior/Dorsal – Top
Inferior/Ventral – Bottom
Lateral - Toward Side
Medial - Toward Middle
Ipsilateral - Same Side
Contralateral - Opposite Side

Question 2

Brain slices and planes

Answer 2

• Frontal/transverse - right angle to the neuraxis (y-axis)
• Sagittal - parallel to neuraxis and perpendicular to the ground (z-axis)
• Horizontal - parallel to the ground (x-axis)

Question 3

What are the main parts in CNS and PNS

Answer 3

CNS: Brain & spinal cord
PNS: Cranial nerves & spinal nerves

Question 4

Features of the brain?

Answer 4

• Soft, jellylike structure (1400g)
• Large mass of neurons, glia and other supporting cells
• Different areas support different functions
• Accounts for only 2% of body weight
• Encased in a tough bony skull and floating in CSF fluid

Question 5

What are the layers of the brain membrane (meninges)?

Answer 5

3 layers of meninges:

• Dura Mater: tough
• Arachnoid: middle, sheet of cellophane draped over
• Pia Mater: last layer, adheres to brain surface

–> Between Arachnoid & Pia Mater: subspace fills with CSF - cerebrospinal fluid

Question 6

What are the ventricular system of the brain?

Answer 6

Ventricles – a set of hollow chambers within the brain filled with CSF

1. Lateral Ventricles
2. Third Ventricles
3. Cerebral Aqueduct
4. Fourth Ventricle

Question 7

What is CSF (cerebrospinal fluid)?

Answer 7

• Similar to blood plasma composition
• Formed by choroid plexus
• Watery cushion protect the brain
• 125-150ml volume & turns over 3-4 times/day
• Actively secreted by the brain (made - circulates - reabsorbed into bloodstream)

Question 8

What are the 3 main parts of the brain AND their subparts

Answer 8

1. Forebrain
   
   • Cerebrum (largest part)
   • Diencephalon
2. Midbrain
   
   • Superior and inferior colliculi (tectum)
   • Substantia nigra (tegmentum)
3. Hindbrain
   
   • Cerebellum
   • Pons
   • Medulla

Question 9

What makes up the cerebrum (forebrain)?

Answer 9

1. Cerebral cortex (outer layer of cerebrum): frontal, temporal, parietal and occipital (FTOP clockwise) -> divided into 2 hemispheres which communicate through corpus callosum.
   - has grey matter (neural cell bodies) AND white matter (neural axon and dendrites)
   - has gyrus (bumps) AND sulcus (ridges/dips)
2. Limbic system: limbic cortex, hippocampus, amygdala, fornix, mammillary bodies
3. Basal ganglia: caudate nucleus, putamen, globus pallidus

Question 10

What are the functions of each part of the cerebrum (forebrain)?

Answer 10

1. Cerebral cortex: contains primary coritices which are responsible for:
   - F: Motor & Somatosensory
   - T: somatosensory associated
   - O: visual
   - T: auditory
2. Limbic system: learning, memory, and emotion
3. Basal ganglia: processing information for motor
   movement

Question 11

What are the functions of each part of the diencephalon?

Answer 11

1. Thalamus: main sensory relay for all senses (except smell) and the cortex.
2. Hypothalamus: involved in homeostasis
   - regulating autonomic NS
   - controlling pituitary glands

Question 12

Structure and function of the midbrain

Answer 12

Tectum:
1. superior colliculi – subcortical sensory pathway involved in fast eye movements (vision)
2. inferior colliculi - part of auditory pathway

Tegmentum: role in motor movement
1. reticular formation
2. red nucleus
3. substantia nigra

Question 13

What are the parts and their functions in the hind-brain?

Answer 13

1. Cerebellum (small brain):
   - Motor co-ordination
   - Regulate smooth & fine movements
2. Pons: relay centre
3. Medulla: regulate and control basic life functions

Question 14

What are the primary components and functions of spinal cord (CNS)?

Answer 14

• CNS tissues extend from medulla (brain)
• Communicate with sensory organs and muscles below head
• 2 parts:
  1. Dorsal roots: info to brain (afferent)
  2. Ventral roots: info from brain (efferent)

Question 15

What are the components and their functions in PNS?

Answer 15

Bring info to and carry info from CNS with 2 parts:

1. Automatic NS:
   - Control vegetative function (life processes)
   - Regulation of smooth muscles, cardiac muscle and glands
   - 2 parts: sympathetic (stress) and parasympathetic (relax post-stress)
   - ALWAYS efferent (does not transmit info to CNS)
2. Somatic NS:
   - Cranial nerves: attached to brain & send and receive signals from head, neck and vagus (digestive organs) - 12 pairs
   - Spinal nerves: attached to spinal cord - 31 pairs to send and receive signal from the rest of the body