Autonomic physiology 1 Flashcards
What is the autonomic nervous system?
Exists to control the things you don’t want to think about, e.g. smooth muscle surrounding blood vessels, airways, bladder, gut & sex organs.
Secretions from glands
Focusing of the eye etc
What is the somatic nervous system?
The somatic nervous system (SNS or voluntary nervous system) is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles. The somatic nervous system consists of afferent nerves or sensory nerves, and efferent nerves or motor nerves
What nervous system is the autonomic nervous system classed with?
The Efferent Nervous System.
The autonomic nervous system consists of a somatic afferent pathway, a central nervous system integrating complex (brain and spinal cord), and two efferent limbs, the sympathetic and the parasympathetic nervous systems
What is the central and peripheral nervous system?
The central nervous system includes the brain and spinal cord, while the peripheral nervous system includes all of the nerves that branch out from the brain and spinal cord and extend to other parts of the body including muscles and organs.
What is the peripheral nervous system divided into?
The autonomic nervous system consists of a somatic afferent pathway, a central nervous system integrating complex (brain and spinal cord), and two efferent limbs, the sympathetic and the parasympathetic nervous systems
What is the junction between a motorneuron and a muscle called?
Neuromuscular Junction (NMJ),
site of chemical communication between a nerve fibre and a muscle cell. The neuromuscular junction is analogous to the synapse between two neurons.
Upon stimulation by a nerve impulse, the terminal releases the chemical neurotransmitter acetylcholine from synaptic vesicles.
What happens to axons in the autonomic nervous system?
Axons are sent out the ventral root but around halfway they synapse onto a second cell then that cell goes out to the periphery.
Differences in autonomic and somatic nervous system
Effectors: somatic effectors are skeletal muscles. Autonomic effectors are smooth muscle,
cardiac muscle and glands.
Efferent pathways: the somatic extends its axons from cell bodies (which are located in the
CNS) to the effectors. The autonomic axons from the CNS synapse in the PNS’s ganglia. A postganglionic
axon continues to the effector.
Target organ responses to their neurotransmitters: the somatic uses ACh and always stimulates
the target. The autonomic can stimulate or inhibit the target. In the autonomic, preganglionic
axons use ACh and postganglionic axons use either ACh or norepinephrine/epinephrine.
What is a ganglion?
A structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fibre.
What are the ganglionic fibres in the ANS?
Pre-ganglionic fibre (small myelinated)
Post-ganglionic fibre (unmyelinated)
Somatic nervous system features
Specialised NMJ.
Ionotropic receptors.
Always excites target.
Autonomic nervous system features
Less specialised junction.
Metabotropic receptors.
May excite or inhibit target.
How does ANS affect smooth muscle?
Smooth muscles inherent tone allows autonomic nervous system to actively contract or relax muscle.
AUTONOMIC
Sympathetic Nervous System
Fight or Flight
The sympathetic nervous system (SNS) controls the body’s responses to a perceived threat and is responsible for the “fight or flight” response.
AUTONOMIC
Parasympathetic Nervous System
Rest and Digest
The parasympathetic nervous system (PNS) controls homeostasis and the body at rest and is responsible for the body’s “rest and digest” function.
