Functional anatomy describes parts of the nervous system that work together to accomplish a particular task for example, visual perception.
Functionally the nervous system consists of the following.
++++++++++++
Motor division (efferent)
Somatic—motor output controlled consciously or voluntarily (eg, by skeletal muscle effectors)
Autonomic—motor output not controlled consciously (eg, by heart or gland effectors)
The autonomic motor nerves, comprising what is often called the autonomic nervous system (ANS), all have pathways involving two neurons: a preganglionic neuron with the cell body in the CNS and a postganglionic neuron with the cell body in a ganglion. The ANS has two divisions: (1) The parasympathetic division, with its ganglia within or near the effector organs, maintains normal body homeostasis. (2) The sympathetic division has its ganglia close to the CNS and controls the body’s responses during emergencies and excitement. ANS components located in the wall of the digestive tract are sometimes referred to as the enteric nervous system.
Somatic—motor output controlled consciously or voluntarily (eg, by skeletal muscle effectors)
Autonomic—motor output not controlled consciously (eg, by heart or gland effectors)
+++++++++++++++++++++++++++++++++++
The autonomic motor nerves, comprising what is often called the autonomic nervous system (ANS), all have pathways involving two neurons: a preganglionic neuron with the cell body in the CNS and a postganglionic neuron with the cell body in a ganglion. The ANS has two divisions: (1) The parasympathetic division, with its ganglia within or near the effector organs, maintains normal body homeostasis. (2) The sympathetic division has its ganglia close to the CNS and controls the body’s responses during emergencies and excitement. ANS components located in the wall of the digestive tract are sometimes referred to as the enteric nervous system.
[In both central and peripheral nerve tissue, neurons typically have numerous long processes for intercellular communication and the various glial cells (Gr. glia, glue) have shorter, more variable processes involved in many neural activities, neural maintenance, and defense.
Neurons respond to environmental changes (stimuli) by altering the ionic gradient that exists across their plasma membranes. All cells maintain such a gradient, also called an electrical potential, but cells that can rapidly change this potential in response to stimuli (eg, neurons, muscle cells, and some gland cells) are said to be excitable or irritable. Neurons react promptly to stimuli with a reversal of the ionic gradient (membrane depolarization) that generally spreads from the place that received the stimulus and propagates across the neuron’s entire plasma membrane. This propagation, called the action potential, the depolarization wave, or the nerve impulse, can travel long distances along the neuronal processes, transmitting such signals to other neurons, muscles, and glands.
By collecting, analyzing, and integrating information in such signals, the nervous system continuously stabilizes the intrinsic conditions of the body (eg, blood pressure, O2 and CO2 content, pH, blood glucose levels, and hormone levels) within normal ranges and maintains behavioral patterns (eg, feeding, reproduction, defense, and interaction with other living creatures).]
Functionally the nervous system consists of the following:
Sensory division (afferent)
Somatic—sensory input perceived consciously (eg, from eyes ears, skin, and musculoskeletal structures)
Visceral—sensory input not perceived consciously (eg, from internal organs and cardiovascular structures)
Motor division (efferent)
Somatic—motor output controlled consciously or voluntarily (eg, by skeletal muscle effectors)
Autonomic—motor output not controlled consciously (eg, by heart or gland effectors)
The autonomic motor nerves, comprising what is often called the autonomic nervous system (ANS), all have pathways involving two neurons: a preganglionic neuron with the cell body in the CNS and a postganglionic neuron with the cell body in a ganglion. The ANS has two divisions: (1) The parasympathetic division, with its ganglia within or near the effector organs, maintains normal body homeostasis. (2) The sympathetic division has its ganglia close to the CNS and controls the body’s responses during emergencies and excitement. ANS components located in the wall of the digestive tract are sometimes referred to as the enteric nervous system.
[In both central and peripheral nerve tissue, neurons typically have numerous long processes for intercellular communication and the various glial cells (Gr. glia, glue) have shorter, more variable processes involved in many neural activities, neural maintenance, and defense.
Neurons respond to environmental changes (stimuli) by altering the ionic gradient that exists across their plasma membranes. All cells maintain such a gradient, also called an electrical potential, but cells that can rapidly change this potential in response to stimuli (eg, neurons, muscle cells, and some gland cells) are said to be excitable or irritable. Neurons react promptly to stimuli with a reversal of the ionic gradient (membrane depolarization) that generally spreads from the place that received the stimulus and propagates across the neuron’s entire plasma membrane. This propagation, called the action potential, the depolarization wave, or the nerve impulse, can travel long distances along the neuronal processes, transmitting such signals to other neurons, muscles, and glands.
By collecting, analyzing, and integrating information in such signals, the nervous system continuously stabilizes the intrinsic conditions of the body (eg, blood pressure, O2 and CO2 content, pH, blood glucose levels, and hormone levels) within normal ranges and maintains behavioral patterns (eg, feeding, reproduction, defense, and interaction with other living creatures).]
Organogenesis, Tissue Structure and Function of the Body Systems
Digital World Medical School
© 2024