Chapter 15 Flashcards
Somatic nervous system
Consist of somatic motor neurons innervate skeletal muscles of the body affect is always excitation
Voluntary control
Autonomic nervous system (ANS)
Regulates cardiac muscle smooth muscles and glands referred to as visceral effectors
Visceral effectors
Associated with the viscera (internal organs) of the body
Bio feedback
Monitoring devices display information about a body functions such as heart rate or blood pressure
Interoceptors
Sensory receptors located in blood vessels, visceral organs, muscles, and the nervous system that monitor conditions in the internal environment
Two main branches of the ANS system
Sympathetic nervous system and parasympathetic nervous system
What’s the term that describes organs that receive nerves from both divisions of the ANS
Dual innervation
Fight or flight response is part of which system?
Sympathetic nervous system
Rest and digest activities are part of which nervous system?
Parasympathetic nervous system
Enteric nervous system
Consists of millions of neurons in plexuses that extend most of the length of the G.I. tract, involuntary
Ganglion
Collection of neuron cell bodies in the peripheral nervous system
Chromaffin cells
Located in the adrenal medulle secrete neurotransmitters epi-nephron and norepinephrine
What are the two motor neurons in any autonomic motor pathway called?
Postganglionic neuron and autonomic ganglion
Where are the preganglionic neuron cell bodies located?
In the lateral horns of the gray matter in the 12 thoracic segments in the first two lumbar segments of the spinal cord
What’s the other name for the sympathetic division?
Thoracilumbar division
What are the axons of the sympathetic preganglionic neurons known as?
Thoracolumnar outflow
Where are the cell bodies of preganglionic neurons of the parasympathetic division located?
In the nuclei of four cranial nerves in the brain stem and in the lateral gray matter of the second through fourth sacral segments of the spinal cord
What’s the parasympathetic division also known as?
Craniosacral division
What are the axons of the parasympathetic preganglionic neurons referred to?
Craniosacral outflow
What are the two major groups of autonomic ganglia?
- Sympathetic ganglia, components of the sympathetic division of the ANS
- Parasympathetic ganglia, components of the parasympathetic division of the ANS
What are the two major sympathetic ganglia?
- Sympathetic trunk ganglia, also called (vertebral chain ganglia or paravertebral ganglia)
- Prevertebral (collateral) ganglia
Sympathetic trunk ganglia
Primarily innervate Organs above the diaphragm such as the head, neck, shoulders, and heart
Prevertebral ganglia
Interview organs below the diaphragm
Where do preganglionic axons of the parasympathetic division synapse with postganglionic neurons?
Terminal ganglia
Where terminal ganglia located?
Within the walls of visceral organs
After axons of sympathetic preganglionic neurons pass sympathetic trunk ganglia what are the four ways they can connect with postganglionic neurons?
- They can synapse with the ganglion they first reach
- An axon me a sand or D sand to a higher or lower ganglion before synapsing with postganglionic neurons passing from ganglion to ganglion
- An axon can continue without synapsing through the sympathetic trunk ganglion to end at the prevertebral ganglion and synapse with postganglionic neurons there
- An axon may also pass without synapse even through the sympathetic trunk ganglion and a prevertebral ganglion on and then extend to chromaffin cells of the adrenal medullae that are functionally similar to sympathetic postganglionic neurons
Autonomic plexuses
Tangled networks Of axons of both sympathetic and parasympathetic neurons in the thorax, abdomen, and pelvis
Major plexuses in the thorax?
Cardiac plexus and pulmonary plexus
Cardiac plexus
Supplies the heart
Pulmonary plexus
Supplies the bronchial tree
The major plexuses of the abdomen and pelvis?
Celiac plexus, superior mesenteric plexus, inferior mesenteric plexus, hypogastric plexus, Renal plexus
Celiac plexus
Largest autonomic plexus surrounds the celiac trunk. distributed to the stomach, spleen, pancreas, liver, gallbladder, kidneys, adrenal medullae, testes, and ovaries
Superior mesenteric Plexus
Supplies the small and large intestine
Inferior mesenteric plexus
Innervates the large intestine also extends through the Hypogastric plexus
Hypogastric plexus
Anterior to the fifth lumbar vertebrae supplies the pelvic viscera
Renal plexus
Supplies the renal arteries within the kidneys and ureters
White ramus
A short pathway that the myelinated preganglionic sympathetic axons pass through
White Rami communicates
Structures containing sympathetic preganglionic axons that connect the anterior ramus of the spinal nerve with the ganglia of the sympathetic trunk
Sympathetic trunk ganglia
Arranged anterior and lateral to the vertebral column, one on either side.
Three cervical 11 or 12 thoracic four or five lumbar four or five sacral sympathetic trunk ganglia and one coccygeal ganglion on
Postganglionic neurons leaving the superior cervical ganglion serve what?
Head and heart
Post ganglionic neurons leaving the middle cervical ganglion and the inferior cervical ganglion inervate what?
Heart and blood vessels of the neck, shoulder, and upper limb
What are the four possible ways axons leave the sympathetic trunk?
- They can enter spinal nerves
- They can form cephalic Periarterial nerves
- They can form sympathetic nerves
- They can form splanchnic nerves
Gray rami communicantes
Structures containing sympathetic postganglionic axons that connects the gang we have the sympathetic trunk to spinal nerves
Cephalic Periarterial nerves
Nerves that extend to the head by wrapping around and following the course of various arteries the pass from the neck to the head provide sympathetic innervation to visceral factors in the skin of the face as well as other visceral factors of the head
Sympathetic nerves
Extend to visceral factors in the thoracic cavity provide sympathetic innervation to the heart and lungs
Sympathetic nerves to the heart
Axons of the postganglionic neurons exit the sympathetic trunk by forming sympathetic nerves enter the cardiac plexus to supply the heart
Sympathetic nerves to the lungs
Sympathetic nerves that enter the pulmonary plexus to supply the smooth muscle of the bronchi and bronchioles of the lungs
Splanchnic nerves
Sympathetic preganglionic axons pass through the sympathetic trunk without terminating in it and beyond the trunk they form these nerves would extend to outline prevertebral ganglia
Splanchnic nerves To abdominal pelvic organs
Most sympathetic preganglionic axons that enters the splanchnic nerves are destined to synapse with sympathetic postganglionic neurons in the prevertebral ganglia that supply the organs of the abdominal pelvic cavity
Splanchnic Nerves to the adrenal medulla
Some sympathetic preganglionic axons pass, without synapsing through the sympathetic trunk, grater splanchnic nerves and Celia ganglion and then extend to chromaffin cells
Chromaffin cells
Similar to sympathetic postganglionic neurons except the lock dendrites and axons rather than extend into another organ however the cells release hormones into the blood releasing a mixture of catecholamine hormones ( 80% epinephrin 20% nor epinephrin and trace amounts of dopamine)
Cell bodies of parasympathetic preganglionic neurons are found where?
Nuclei in the brainstem and in the lateral gray matter of the second through fourth sacral segments of the spinal cord
Cranial parasympathetic outflow
Consists of pre-ganglionic axons that extend from the brain stem in for cranial nerves
Sacral parasympathetic outflow
Consists of preganglionic axons in anterior roots of the second through fourth sacral spinal nerves
What are the four pairs of cranial outflow ganglia and the ganglia associated with the vagus 10 nerve
- Ciliary ganglia - innervate smooth muscle fibres in the eyeball
- PterygoPalatine ganglia - sends postganglionic axons to the nasal mucosa, palate, pharynx, and lachrymal glands
- Submandibular ganglia - Send postganglionic axons to the submandibular and sub lingual salivary glands
- Otic ganglia - Send postganglionic axons to the parotid salivary glands
Preganglionic axons that leave the brain is part of the biggest 10 nerves carry what amount of the total craniosacral outflow?
80%
Pelvic splanchnic nerves
Intervae smooth muscle in glands in the walls of the colon, ureters, urinary bladder, and reproductive organs
Cholinergic neurons
Release the neurotransmitter acetylcholine
In the ANS the cholinergic neurons include what?
- All sympathetic and parasympathetic preganglionic neurons
- Sympathetic postganglionic neurons that innervate most sweat glands
- All parasympathetic postganglionic neurons
Two types of cholinergic receptors?
- Nicotinic receptors
- Muscarinic receptors
Both bind acetylcholine
Nicotinic receptors
Present in the plasma membrane of dendrites and cell bodies of both sympathetic and parasympathetic postganglionic neurons, the plasma membranes of chromaffin cells of the adrenal medullae, and in the motor end plate at the neuromuscular junction
Muscarinic receptors
Present in the plasma membranes of all the effectors (Smooth muscle, cardiac muscles, and glands) innervated by parasympathetic postganglionic axons
Adrenergic neurons
Releases norepinephrine
Adrenergic receptors
Find both norepinephrine and I’ve been a friend two main types are alpha receptors and beta receptors
Catechism-O-methyltransferase or monoamine oxidase
Enzymatically inactivates norepinephrine
Agonist
A substance that binds to an activate a receptor in the process mimicking the fact of a natural neural transmitter or hormone
Antagonist
Is a substance that binds to and blocks a receptor thereby preventing a natural neurotransmitter or hormone from exerting its effects
Autonomic tone
Regulated by the hypothalamus is a balance between sympathetic and parasympathetic activity
Effects of the fight or flight response
- Pupils of the eyes dilate
- Heart rate, force of heart contraction, and blood pressure increase
- Airways dilate allowing faster movement of air into and out of the lungs
- The blood vessels that supply the kidneys and the gastrointestinal tract constrict which decreases blood flow through these tissues that result in the slowing of urine formation and digestive activities which are not essential during exercise
- Blood vessels that supply organs involved in exercise or fighting of danger-Skeletal muscles, cardiac muscle, liver, and Adipose tissue- Dilate, allowing greater blood flow through these tissues
- Liver cells perform glycogenolysis (breakdown of glycogen to glucose) and adipose tissue cells perform Lipolysis (breakdown of triglycerides to fatty acids and glycerol)
- Release of glucose by the liver increases blood glucose level
- Processes that are not essential for meeting the stressful situation or inhibited for example muscular movement of the gastrointestinal tract and digestive secreation slow down or even stop
Why are sympathetic stimulation longer lasting and more widespread than the affects of parasympathetic stimulation?
- Sympathetic postganglionic axons diverge more extensively as a result many tissues are activated simultaneously
- Acetylcholinesterase quickly inactivates acetylcholine but norepinephrine lingers in the synaptic cleft for longer periods
- Epi-nephron and norepinephrine secreted into the blood from the adrenal medulla intensify and prolong the response caused by norepinephrine liberated from the sympathetic postganglionic axons circulating through the body affecting all tissues that have alpha and beta receptors
“Rest and digest”, What are the five parasympathetic responses?
- Lacrimation
- salvation
- urination
- digestion
- defaecation
“ Rest and digest” the 3 decreases
- Decrease heart rate
- Decrease diameter of airways (bronchoconstriction)
- Decrease diameter (constriction) of the pupil’s
Autonomic (visceral) reflexes
Responses that occur when nerve impulses pass through an autonomic reflex ark play Keii role in regulating controlled conditions in the body such as blood pressure by adjusting heart rate force of ventricular contraction in blood vessel diameter
Components of the autonomic reflex arc
- Sensory receptor
- Sensory neuron
- Integrating centre
- Motor neurons
- Effector
What is the major control in integration centre of the ANS?
Hypothalamus
Why are most parasympathetic preganglionic axons longer than most sympathetic preganglionic axons?
Because most parasympathetic ganglia are in the walls of visceral organs but most sympathetic ganglia are close to the spinal cord in the sympathetic trunk
What is the largest autonomic plexus?
Celiac (solar) plexus
Where does the pelvic splanchnic nerve branch to?
From the second through fourth sacral spinal nerves
