Untitled Quiz

The nervous system is comprised of the central nervous system (CNS) and the peripheral nervous system (PNS).
The CNS is the "central hub" that processes information and coordinates body functions.
The PNS consists of the nerves that carry information between the CNS and the rest of the body.
The PNS includes 12 pairs of cranial nerves and 31 pairs of spinal nerves.

The CNS encompasses the brain and spinal cord.
The human brain contains about 100 billion neurons and 1000 billion glial cells.
The brain utilizes about 20% of the body's total energy.
The brain requires a constant supply of oxygen and glucose to function.
Brain damage can occur if oxygen supply is cut off for 4 to 5 minutes or glucose supply is cut off for 10 minutes.

The brain can be divided into four lobes: temporal, parietal, occipital, and frontal.
Temporal lobe: Responsible for processing auditory information, including the auditory cortex.
Occipital lobe: Processes visual information and houses the visual cortex.
Parietal lobe: Integrates sensory information such as touch, spatial awareness, and navigation.
Frontal lobe: Involved in attention, reward, short-term memory, motivation, and planning. It contains the primary motor cortex responsible for voluntary movement.

The spinal cord runs the length of the back, transmitting information between the brain and the body.
It connects to the brain via the brainstem and contains 31 spinal nerves that branch out to connect with the nerves of the PNS.
Motor commands sent from the brain travel through the spinal cord to the body's muscles.

The PNS is further divided into the afferent (sensory) and efferent (motor) divisions.
Afferent division: Carries information from the body to the CNS.
Efferent division: Carries information from the CNS to the body.

The efferent division is divided into the somatic and autonomic nervous systems.
Somatic Nervous System: Controls voluntary movements. Examples include the motor neurons supplying skeletal muscle.
Autonomic Nervous System (ANS): Controls involuntary functions. It supplies cardiac muscle, smooth muscle, and glands.

There are three functional types of neurons:
- Afferent neurons (sensory neurons): Carry information from the body to the CNS.
- Efferent neurons (motor neurons): Carry information from the CNS to the body.
- Interneurons: Found within the CNS. They connect and communicate with other neurons. About 99% of the brain's neurons are interneurons.

Afferent neurons have sensory receptors, which convert external stimuli into nerve impulses.
These impulses travel along the neuron's axon toward the spinal cord.

Efferent neurons are located in the PNS.
Their cell bodies are located in the CNS.
The efferent axon leaves the cell body and travels to the target organ or muscle.

Interneurons are located within the CNS.
They are responsible for complex processing and integration of information between other neurons in the CNS.

The CNS can be divided into white and gray matter.
Gray matter: Contains mostly neuron cell bodies and dendrites.
White matter: Contains mostly myelinated axons.
The brain has an outer cortex of gray matter and an inner area of white matter.
Both white and gray matter contain glial cells, which support and protect neurons.

CSF is produced by the choroid plexuses, capillaries in the pia mater of the brain's ventricles.
It circulates around the brain and spinal cord.
It is crucial for maintaining brain health and function.
The volume of CSF is typically 125-150 ml.

Hydrocephalus is a condition where excess CSF accumulates in the brain, often due to a blockage in the circulation or reabsorption of CSF.
If untreated, hydrocephalus can lead to brain damage and intellectual disability.
Treatment can involve surgically shunting the excess CSF to veins in other parts of the body.