Nervous System Physiology Quiz

Nervous System Physiology

• The nervous system is composed of the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS consists of the brain and spinal cord.
• The brain is divided into four regions: cerebrum, diencephalon, brainstem, and cerebellum.
• The brainstem consists of the midbrain, pons, and medulla oblongata.
• The cerebrum and diencephalon together constitute the forebrain.
• The brain contains four interconnected cavities, the cerebral ventricles, which are filled with cerebrospinal fluid (CSF).
• CSF is formed by specialized capillaries called choroid plexus and cushions the CNS.
• The blood-brain barrier (BBB) is a structural arrangement of capillaries that selectively determines which substances can move from the blood into the brain.
• Oxygen and glucose are necessary for brain survival and move freely across the BBB.
• Harmful substances like toxins are prevented from crossing into the brain.
• The cerebrum is the largest portion of the forebrain overseeing sensory and motor activities, perception, emotions, consciousness, memory, and voluntary movements.
• The cerebrum is divided into two hemispheres and covered in a surface or cortex arranged in bulging folds (gyrus) and furrows (sulcus).
• The cortex is further divided into four lobes: frontal, parietal, temporal, and occipital.
• The frontal lobe focuses on motor activity and personality.
• The parietal lobe manages language and senses of temperature, pressure, and touch.
• The temporal lobe contains centers for hearing, smell, and language input.
• The occipital lobe is associated with vision.
• The cerebellum is the second-largest part of the brain, connecting to every part of the CNS; coordinating voluntary and involuntary movements, and adjusting muscles for maintaining posture.
• The diencephalon includes the thalamus and hypothalamus.
• The thalamus is a relay center for sensory impulses, excluding olfactory and motor areas of the cortex.
• The hypothalamus controls behavior, emotional expression, body temperature, many metabolic activities, and hormonal secretions of the pituitary gland.
• The brainstem controls visual reflexes and hearing, and plays a role in visceral control.
• The medulla oblongata connects the rest of the brain to the spinal cord and regulates breathing, swallowing, coughing, sneezing, vomiting, heartbeat, and blood pressure.
• The spinal cord is a slender, cylinder-shaped tissue within the bony vertebral column.
• The 44 cm long spinal cord is shorter than the spinal column, and its segments do not perfectly correspond to the vertebrae.
• The spinal cord contains a central butterfly-shaped area of gray matter composed of interneurons, cell bodies and dendrites of efferent neurons, entering axons of afferent neurons, and glial cells.
• The spinal cord conducts impulses to and from the brain. In most instances, sensory information traveling up the right side of the spinal cord crosses over to the left side of the brain.
• The peripheral nervous system (PNS) transmits signals between the CNS and receptors and effectors in other parts of the body.
• The PNS has 43 pairs of nerves: 12 pairs of cranial nerves and 31 pairs of spinal nerves, connecting to the spinal cord.
• Spinal nerves are named by their vertebral exit points: cervical, thoracic, lumbar, sacral, and coccygeal.
• Cranial nerves control aspects of sensation and muscular activity in the head and neck.
• Spinal nerves connect and transmit messages directly to the spinal cord.
• Afferent fibers control sensory, while efferent fibers controls motor actions.
• The efferent division of the PNS is more complicated than the afferent, being subdivided into the somatic and autonomic nervous systems.
• The somatic nervous system is comprised of motor neurons leading to skeletal muscles.
• The autonomic nervous system controls involuntary functions of the body.
• The autonomic nervous system consists of two neurons that connect to the CNS and effector cells.
• Sympathetic and parasympathetic divisions make up the ANS.
• Sympathetic is the fight or flight response, increased alertness.
• Parasympathetic is the rest and digest response.
• The sympathetic fibers exit the spinal cord at the thoracic and lumbar regions, while parasympathetic fibers exit the brainstem and the sacral region.
• Differences lie in ganglionic location and neurotransmitters.
• In the parasympathetic division, acetylcholine (ACh) is the neurotransmitter between postganglionic neurons and effector cells.
• In the sympathetic division, norepinephrine is the neurotransmitter between postganglionic neuron and effector cells.

Additional Notes

• The autonomic nervous system (ANS) has both sympathetic and parasympathetic divisions, each with distinct anatomical origins, functions, and physiological actions.
• The sympathetic division is responsible for the "fight-or-flight" response, while the parasympathetic division is responsible for the "rest-and-digest" response.
• Ganglia function as clusters of cell bodies outside the CNS, mediating between preganglionic and postganglionic neurons in the ANS.