brain parts

Question 1

Describe the structure of the spinal cord

Answer 1

• Pair of spinal nerves enter the cord:
• Dorsal Sensory
• Ventral Motor
• Gray matter in central H shape form (in transverse cut)
• includes neuronal connections that provide for spinal reflexes
• white matter in periphery
• contains
  1) axons that convey sensory data to the brain.
  2) axons that conduct impulses, typically motor, from brain to spinal cord.

Question 2

Describe the structure of the Medulla oblongata

Answer 2

1. Fiber tracts from the spine continue to the medulla
2. Contain nuclei – the most noticeable – inferior olivary nuclei
3. The inferior olivary nuclei sends fiber through the inferior cerebellar peduncles attaching the medulla oblongata and the cerebellum
4. smaller nuclei are components of the cranial nerves (IX, X, XI, XII)

Question 3

What is the difference between ascending and descending fiber tracts

Answer 3

The descending tracts are neural pathways by which motor signals are sent from the brain to lower motor neurons and then muscles

The ascending tracts are neural pathways by which sensory signals from the peripheral nerves is transmitted to the brain

Question 4

Describe the structure of the Pons

Answer 4

The pons consist of two main parts

The dorsal portion – The tegmentum

Has features share with other parts of the brain as it includes ascending and descending

Tracts ,and some nuclei of cranial nerves (V, VI, VII, VIII)

The ventral portion or_- basal pons_

Special to the pons – provides extensive connections between a cortex of a cerebral hemisphere and its contralateral cerebellar hemisphere , in order to maximize efficiency of motor activities

The pons connect to the cerebellum through the pair of middle cerebellar peduncles

Question 5

Describe the structure and functions of midbrain

Answer 5

• Contains ascending and descending pathways
• The dorsal part the Tectum relates mostly to visual & auditory systems
• contains 2 prominent nuclei the red nucleus & Substanina nigra relating to motor control
• Contains nuclei for 2 cranial nerves(III& IV)
• attached to the cerebellum via the superior cerebellar peduncles

Question 6

Describe the functions of the cerebellum

Answer 6

• it uses data it receives from sensory systems and the cerebral cortex
• influences motor neurons that relate to the skeletal muscles
• it influences muscle tone in relation to equilibrium locomotion and posture
• it coordinates the timing, force and extent of contraction of muscles used for skilled movement
• operates on a subconscious level

Question 7

What are the components of the diencephalon

Answer 7

• Thalamus
• hypothalamus
• epithalamus
• subthalamus
• retina is also a derivative

Question 8

Describe the thalamus (and nuclei)

Answer 8

• parts receive sensory data from sensory system and project it to sensory areas at the cerebral cortex
• connection with cortical areas relating to complex mental processes
• regions that are part of neural circuits related to emotions
• some nuclei incorporated into pathways from cerebellum and corpus striatum to motor areas

of the cerebral cortex

Question 9

what are neural circuits

Answer 9

A neural circuit is a population of neurons interconnected by synapses to carry out a specific function when activated

Question 10

What are neural tracts

Answer 10

neural pathways in the CNS Each tract runs bilaterally; one on each side of the cerebral hemisphere or in a hemisection of the spinal cord , some crossover to descend or ascend on the contralateral side

Question 11

what is in the epithalamus

Answer 11

small tracts and nuclei, pineal gland, habenula, habenular commissure, stria medullaris, posterior commissure

Question 12

describe functions of the hypothalamus

Answer 12

• controlling influence over sympathetic and parasympathetic systems
• relating to internal organs, exocrine glands and blood vessels
• neuro secretory cells synthesize hormones that enter the bloodstream
• relating to kidneys , piturity gland hormonal output
• some origin from olfactory placode and secrete – gonadotrophin -releasing hormone
• migrate along the teminal nerve TINY CN 0

Question 13

What is included in the subthalamus

Answer 13

• sensory tracts that proceed to the thalamus
• axons that originate in the cerebellum and corpus striatum
• the subthalamic nucleus

Question 14

What is included in the telencephalon

Answer 14

the cerebral cortex ,corpus striatum and cerebral white matter

Question 15

what are the functions of the cerebral cortex

Answer 15

• sensation and motor functions in distinct regions
• association cortex for heist neural function including intellectual

Question 16

What is the corpus stratum

Answer 16

Large mass of gray matter with motor functions at the base of each hemisphere

Consists of caudate and lentiform nuclei (parts of the basal ganglia)

Question 17

What is included in the cerebral white matter (medullary center)

Answer 17

• fibers connecting cortical area of same hemisphere
• fibers crossing the midline (corpus callosum) connecting the two hemispheres
• fibers that that pass in both directions between the cortex and subcortical parts of CNS that

converge to form the internal capsule in the region of thalamus and corpus striatum

Question 18

what is the weight of the human brain as it develops (and what grows)

Answer 18

-400 g at birth , 1200g at age 3 and minor rise until 18

Most of the growth continuing formation of synaptic connections, production

of neuroglial cells, and thickening of the myelin sheaths around axons