Organization Of The Human Nervous System Flashcards
Peripheral Nervous System (PNS)
The part of the vertebrate nervous system that is located outside the skull and spine
Central Nervous System (CNS)
The part of the vertebrae nervous system that is located within the skull and spine
Cervical region
The section of the spine that provides the flexible framework of the neck or cervix; it lies between the skull and the thoracic region
Thoracic region
The section of the spine to which the ribs are attached; it lies between the cervical and the lumbar regions
Lumbar region
The section of the spine that supports the small of the back; it lies between the thoracic region and the sacral region
Sacral region
The section of the spine to which the bones of the pelvis are attached; it lies adjacent to the lumbar region
Functions of the PNS
- conducts sensory signals to the CNS from sensory receptors in various parts of the body
- conducts motor signals away from the CNS to muscles, glands, and other effector organs in various parts of the body
Brain
The part of the central nervous system that is located in the skull
Spinal cord
The part of the central nervous system that is located in the spine
Divisions of the Central Nervous System
The brain and the spinal cord
Functions of the spinal cord
- receives signals from the sensory fibers of the PNS and conducts them to the brain for complex analysis
- receives signals from the brain and conducts them to the motor fibers of the PNS
- performs the simple rapid analyses that mediate many of our reflexive responses
Somatic nervous system
The division of the peripheral nervous system that interacts with the external environment; it conducts sensory signals to the CNS from external receptors and receptors in joints and skeletal muscles, and it conducts motor signals from the CNS to skeletal muscles
Autonomic nervous system
The division of the peripheral nervous system that participates in the regulation of the body’s internal environment; it conducts sensory signals to the CNS from the receptors in internal organs, and motor signals from the CNS back to the same internal organs
Spinal gray matter
The H-shaped area of gray nervous tissue in the core of the spinal cord
Spinal white matter
The area of white nervous tissue in the spinal cord; it surrounds the spinal gray matter
Dorsal roots
The 31 pairs of sensory nerves that enter the spinal cord; they enter the spinal cord’s dorsal surface
Ventral roots
The 31 pairs of motor nerves that exit the spinal cord; they project from the spinal cord’s ventral surface
Afferent nerves
Nerves that carry signals toward a structure (in regard to the structure)
Efferent nerves
Nerves that carry signals away from a structure (in regard to the structure)
Sympathetic nervous system
One of the two motor divisions of the autonomic nervous system; it tends to mobilize energy resources during periods of threat; sympathetic nerves project from the thoracic and lumbar regions of the spinal cord
Parasympathetic nervous system
One of the two motor divisions of the autonomic nervous system; it tends to conserve energy during periods of quiescence; parasympathetic nerves project from the brain and from the sacral region of the spinal cord
Pituitary gland
The gland that hangs from the hypothalamus; because it releases tropic hormones, it is often referred to as the master gland
Hypothalamus
The brain structure from which the pituitary is suspended; it secretes releasing hormones, which stimulate the release of tropic hormones from the pituitary
Adrenal medulla
The core of the adrenal gland; it is activated by the sympathetic nervous system, and in turn it secretes hormones whose effects are similar to those of the sympathetic nervous system
Adrenal cortex
The outer layer of the adrenal gland; it releases hormones that regulate energy metabolism, mineral balance, and reproductive behavior
Gonads
The sex glands (i.e., ovaries in women and testes in men); they release hormones that influence both the development of female and male reproductive systems and the reproductive behavior of adults
