A&P 10

Two main parts of the nervous system

Central nervous system (CNS) and peripheral nervous system (PNS)

What does the central nervous system consist of?

The brain and spinal cord

How many neurons are approximately found in the human brain?

About 86 billion neurons

Three major regions of the brain

Forebrain, midbrain, and hindbrain

Two components of the forebrain

Diencephalon and telencephalon

Structures in the diencephalon

Thalamus, hypothalamus, and pineal gland

Function of the thalamus

Serves as a major relay station for almost all sensory information, directing it to cerebral cortex

Role of the hypothalamus

Controls hunger, thirst, body temperature, sleep/wake cycles, and regulates hormone release through pituitary gland

What hormone does the pineal gland secrete, and what is its primary function?

Melatonin; it regulates the sleep-wake cycle

Largest and most complex part of the brain

Telencephalon (cerebrum)

Parts of the telencephalon

Basal ganglia, olfactory bulbs, and cerebrum

Basal ganglia

Control and coordinate voluntary movements. Also help in learning and memory, decision-making, planning and goal-directed behavior, and habit formation.

Olfactory bulbs

First to process sense of smell

Cerebrum

Two hemispheres, covered by layer of gray matter called cerebral cortex. Initiates and coordinates voluntary movements and is responsible for higher-order cognitive processes.

Four lobes of the cerebrum

Frontal, parietal, temporal, and occipital lobes

Frontal lobe

Controls voluntary movement, executive functions, personality, and speech. Contains Broca's area.

Parietal lobe

Processes sensory information like touch, temperature, and pain. Also plays a role in spatial awareness and language.

Temporal lobe

Processes auditory information, stores memories, and helps understand language. Contains Wernicke's area.

Occipital lobe

Processes visual information

Structures of hindbrain

Cerebellum, pons, and medulla oblongata

Cerebellum

Coordinates voluntary movements, maintains balance and posture, and contributes to motor learning

Pons

Regulates breathing and bladder function (micturition).

Medulla oblongata

Regulates heart rate, blood pressure, and breathing

Difference in cerebrum and cerebellum

The cerebrum initiates voluntary movement; the cerebellum fine-tunes and coordinates it

Midbrain

Controls eye movements, pupillary reflexes, and processes auditory information

Types of meninges

Dura mater, arachnoid mater, and pia mater

Spaces between meninges

Epidural space, subdural space, subarachnoid space

Cerebrospinal fluid (CSF)

Cushions the brain and spinal cord, providing buoyancy, nourishment, and protection. Subarachnoid space is filled with cerebrospinal fluid.

Length of the spinal cord in adults

About 45 cm (18 inches)

Five regions of the spinal cord

Cervical, thoracic, lumbar, sacral, and coccygeal regions

Functions of the spinal cord

Sensory function, motor function, reflex control, and autonomic function

Sensory function of spinal cord

Receiving sensory information and transmitting it to the brain for processing

Motor function of spinal cord

Sends motor commands from the brain to muscles throughout the body

Reflex control in spinal cord

Mediates simple reflexes without involving the brain for rapid responses

Autonomic function in spinal cord

Controls involuntary bodily functions and maintains homeostasis