Learning Objectives Pinel Ch. 3 Nervous System

Question 1

List and describe the major divisions of the nervous system

Answer 1

• CNS and the PNS (cns is the brain and spinal cord and the pns is outside the skull and spine)
• the pns is composed of the somatic and autonomic nervous systems
• the somatic nervous system is composed of afferent nerves carrying signals from the extremities to brain and efferent nerves carrying motor sginals from the cns to the extremities.
• the autonomic nervous system has afferent nerves that carry signals from the internal organs of the cns and efferent nerves carrying motor signals from the cns to the internal organs.
• the autonomic nervous system has 2 kinds of efferent nerves sympathetic and parasympathtic.
• sympathetic nerves are autonomic motor nerves tha proect from CNS in the lumber (small back) to the thoracic (chest area)
• parasympathetic nerves are those autonomic motor nerves that project from the brain and sacral (low back0 to the spinal cord.
• sympathetic nerves stimulate organize and mobilize energy resources in threatening situations whereas parasympathetic conserve energy.

Question 2

Describe the 3 meninges and explain their functional role

Answer 2

• menginges are protective membranes for the brain
• the outer meninx is a tough membrane called the dura meter, immediatly inside is the fine arachnoid membrane, beneath this membrane is a space called the sub arachnoid space whcih contains large blood vessels and cerebrospinal fluid. Then the inner motst meninx is the pis mater which adheres to the surface of the cns.

Question 3

Explain where cerebrospinal fluid is produced and where it flows

Answer 3

• the fluid flows in the central canal (the smallest central channel that runs the length of the spinal cord) and in the cerebral ventrciles (four large internal chambers of the brain 2 lateral and a 3rd and 4th.
• it is produced in the choroid plexuses
• the fuld supports and cushions the brain.

Question 4

Explain what the blood brain barrier is and what functional role it serves

Answer 4

• in the brain the blood vessels are tightly packed to stop proteins and large cells rom entering the brain as they may be dangerous.
• this impeded the passage of many toxic substances from the blood to the brain.
• good large molecules are transported.

Question 5

describe 4 kinds of glial cells

Answer 5

• oligodendrocytes - are glial cells with rentensions that wrap around the axons of some neurons in the CNS. These extensions create myelin shealths that increase speed and efficiency of axonal conduction.
• Schewan cells - perform similarly but in the PNS. schewan cells contribute one myelin segment whereas oligodendrocytes provide several. Schewan cells can guide axonal regeneration after damage no oli.
• microglia - small, respond to injruy or diease by multiplying, engulfing cellular debris/ entre cells and triggering the inflammatory response.
• astrocytes - largest and shpaed like stars, their extensions cover the outer surfaces of the blood vessels that course through the brain they also make contact with some neurons. these particular astrocytes allow the passage of come chemicals from the blood to the cns and block others.

Question 6

what are the cross sections of the spinal cord

Answer 6

• medial - to the middle to the spine/brain
• lateral - towards the outside
• dorsal- is towards the fin (think humans are on four legs)
• anterior - forehead
• posterior - near butt or back of head
• ventral towards the chest (or down from the chin)

Question 7

List and discuss the five major divisions in the human brain

Answer 7

forebrain, midbrain, hindbrain
telencephalon, diencephalon,
mescencephalon (mid brain)
metencephalon,
myelencephalon

Question 8

List and describe the components of the myelencephalon

Answer 8

The Medulla - most posterior division of the brain that is largely composed of tracts carrying signals between the rest of the brain and the body. Part of the myelencephalon is the reticular formation (net) of 100 tiny nuclei that occupy the cntral core of the brain stem involved in sleep, attention, movement, the maintenance of muscle tone, cardiac circulatory and respiratory reflexes.

Question 9

list and describe the components of the metencephalon

Answer 9

like the myelencephalon the metencephalon how’s many tracts and is apart of the reticular formation these structures create a bulge called the pons. The pons is one major division of the metencephalon the other is the cerebellum. The cerebellum helps control ones movements and adapt to changing conditions.

Question 10

List and describe the mesencephalon

Answer 10

has 2 divisions, the tectum and the tegmentum. tectum is the dorsal space of the midbrain. the tegmentum is the division of the mesencephalon ventral to the tectum.

Question 11

List and describe the diencephalon

Answer 11

the thalamus and the hypothalamus are here. The hypothalamus is just below the anterior thalamus and plays a role in eating sleeping and sex via the pituitary gland.

Question 12

list and descibe the telencephalon

Answer 12

largest division of the human brain. It initiates voluntary movements, interprets sensory information, learning, speaking, problem solving, Cerebral cortex is a layer of tissue that is composed by unmyelinated neurons (grey matter) the layer beneath is composed of white matter (myelinated)

Question 13

List and describe the components of the limbic system and the basal ganglia

Answer 13

• the limbic system, is involved in the regulation of motivated behaviours including fleeing, feeding, fighting and sexual behaviour
• the basal ganglis plays a role is voluntary motor response and decision making