69 Questions
What is the primary function of the blood-nerve barrier?
To maintain the fiber's environment
What type of nerve fiber innervates the brain?
Cranial nerve
What is the main component of the peripheral nervous system?
Nerves
What is the purpose of the endoneurium?
To cover the axon and myelin sheath
What type of ganglion is composed of cell bodies of nerve fibers?
Any of the above
What is the function of the perineurium?
To surround bundles of axons
What is the classification of a nerve fiber that innervates the spinal cord?
Spinal nerve
What is found in the endoneurium besides axons?
Reticular fibers, scattered fibroblasts, capillaries, and occasional mast cells and macrophages
What is the primary factor that determines the flow of blood in capillaries?
The flow of blood from arterioles
What is the function of sweat glands during stressful situations?
To reduce heat
What is the effect of sympathetic stimulation on salivary glands?
Decreases salivary secretion
What is the relationship between the sympathetic and parasympathetic nervous systems in salivary glands?
Synergistic
Which of the following nervous systems is responsible for the 'fight or flight' response?
Sympathetic nervous system
What is the effect of parasympathetic stimulation on salivary glands?
Increases salivary secretion
What is the primary function of the sympathetic nervous system in arterioles?
To constrict arterioles
What is the relationship between the sympathetic and parasympathetic nervous systems in terms of their functions?
Antagonistic
What is the name of the division of the efferent nervous system that receives no mention in the classification of the nervous system into somatic and autonomic nervous systems?
Enteric Nervous System
What type of stimuli can afferent neurons receive?
Either sensory or visceral stimuli
What is the primary function of the sympathetic nervous system in emergency situations?
To promote responses that prepare the body for strenuous physical activity
Which type of glands are innervated by only the sympathetic nervous system?
Sweat glands
What is the characteristic of the dual innervation of organs by both sympathetic and parasympathetic fibers?
It produces opposite effects in a particular organ
What is the location of the enteric nervous system?
Within the wall of the digestive tract
What is the direction of travel of afferent fibers compared to efferent fibers?
In the opposite direction
What is the general effect of the parasympathetic nervous system on the body's activity?
It inhibits actions that prepare the body for strenuous physical activity
What type of receptors are activated by nicotine and can be found on postganglionic cell bodies of all autonomic ganglia?
Nicotinic Receptors
What is the result of IP3 binding to a receptor in the sarcoplasmic reticulum?
Opening of the Ca2+ channel
What is the effect of NE binding to an alpha receptor?
Activation of phospholipase C
What is the function of muscarinic receptors in the heart?
Decrease the rate of contraction
What is the effect of ACh on the heart when it binds to a muscarinic receptor?
Decrease the rate of contraction
What is the mechanism of action of Metoprolol?
Blocks beta1-adrenergic receptors
What is the effect of Salbutamol on the bronchioles?
Dilation of the bronchioles
What is the primary mechanism involved in the activation of β1 adrenergic receptor?
G protein-coupled mechanism
What is the effect of phosphorylation of sarcoplasmic reticulum receptors in the heart?
Increased release of Ca2+ ions
Which region of the CNS is NOT involved in the control of skeletal muscle activity?
Occipital lobe
What is the effect of Ca2+ ion binding to troponin in the heart?
Increased actin-myosin interaction
What is the primary neurotransmitter released by motor neurons at the neuromuscular junction?
Acetylcholine
What is the effect of activation of protein kinase in the heart?
Phosphorylation of sarcoplasmic reticulum receptors
What is the characteristic of the motor end plate at the neuromuscular junction?
Has no threshold potential
What is the term for the progressive degeneration of motor neurons, as seen in Lou Gehrig's disease?
Amyotrophic Lateral Sclerosis (ALS)
What is the purpose of the perineurium in the peripheral nervous system?
To form the blood-nerve barrier and prevent the passage of molecules
What is the classification of a nerve fiber that comes from the brain?
Cranial nerve
What is the function of the endoneurium in the peripheral nervous system?
To surround individual axons and maintain their environment
What is the term for the bundles of axons in the peripheral nervous system?
Fascicles
What is the term for the cell bodies of neurons outside the central nervous system?
Ganglia
What is the purpose of the reticular fibers in the endoneurium?
To provide structural support to the nerve fibers
What is the type of connective tissue found in the outermost covering of a nerve?
Dense irregular connective tissue
What is the term for the blood vessels found in the epineurium?
Arteries and veins
What is the function of mast cells and macrophages in the nervous system?
To kill microorganisms that enter the axons
What is the characteristic of the superficial region of the epineurium compared to the deeper region?
The superficial region is more dense, while the deeper region is more loose
What is the location of capillaries in a nerve?
In each fascicle
What is the shape of arteries compared to veins in the epineurium?
Arteries are more circular, while veins are more flat
Which type of neuron is responsible for integrating afferent information and formulating an efferent response?
Interneuron
What is the direction of travel of the signal in an afferent fiber?
From the receptor to the CNS
What is the site of release of neurotransmitters in an efferent neuron?
Axon terminal
Which part of the neuron receives the signal from the afferent neuron?
Dendrites
What is the function of the axon terminal of the efferent neuron?
To transmit the signal to the effector organ
What is the site of integration of afferent information?
Interneuron
What is the primary characteristic of the cell bodies in sensory ganglia?
They are pseudounipolar neurons
What is the function of the satellite glial cells in ganglia?
They provide nutrition to the neurons
What is the characteristic of lipofuscin in ganglia?
It is a pigment that increases with age
What is the difference between sensory ganglia and autonomic ganglia?
Sensory ganglia have a more distinct capsule
What is the characteristic of the efferent nerve pathways in the autonomic nervous system?
They consist of a two-neuron chain
What is the type of neuron found in autonomic ganglia?
Multipolar neurons
What is the primary function of the adrenal cortex?
To secrete glucocorticoids essential for metabolism
What is the effect of alpha 1 receptors on arterioles?
Constriction
What is the primary messenger system used by beta 1 receptors?
cAMP
Which type of receptors have a greater sensitivity towards norepinephrine?
Alpha 1 receptors
What is the effect of beta 2 receptors on bronchioles?
Dilation
Which type of receptors are inhibitory, and found mainly in the smooth muscles of the digestive tract?
Alpha 2 receptors
Study Notes
Organization of the Vertebrate Nervous System
- The Peripheral Nervous System (PNS) surrounds bundles of axons (fascicles)
- The PNS has two divisions: Afferent Nervous System and Efferent Nervous System
Afferent Nervous System
- Receives and transmits sensory information from the periphery to the Central Nervous System (CNS)
- Consists of afferent neurons that inform the CNS about conditions in the external and internal environment
- Can receive either sensory (outside) or visceral (inside) stimuli
Efferent Nervous System
- Transmits motor signals from the CNS to effector organs (muscles and glands)
- Consists of efferent neurons that carry instructions from the CNS to effector organs
- Divided into Somatic Nervous System and Autonomic Nervous System
Somatic Nervous System
- Innervates skeletal muscles (voluntary control)
- Consists of motor neurons that release neurotransmitter ACh, stimulating muscle contraction
- Includes motor neurons that originate in the spinal cord or brain stem and end on skeletal muscles
Autonomic Nervous System (ANS)
- Innervates smooth muscles, cardiac muscles, and glands (involuntary control)
- Divided into Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PNS)
- SNS dominates in emergency or stressful situations, promoting responses that prepare the body for strenuous physical activity
- PNS has a more general function, promoting rest and digestion
Neuron Classification
- Afferent neurons: inform CNS about conditions in the external and internal environment
- Efferent neurons: carry instructions from CNS to effector organs
- Interneurons: found entirely within CNS, integrating afferent information and formulating an efferent response
Receptors and Neurotransmitters
- Adrenergic Receptors (α and β): respond to Norepinephrine (NE) and Epinephrine (E)
- Cholinergic Receptors (nicotinic and muscarinic): respond to Acetylcholine (ACh)
- α receptors: cause muscle contraction and vasoconstriction
- β receptors: cause muscle relaxation and vasodilation
- NE and E bind to α and β receptors, with differing affinities
- β1 receptors: found in the heart, respond to NE and E
- β2 receptors: found in the bronchioles, respond to E
This quiz covers the peripheral nervous system, including efferent and afferent nervous systems, autonomic and somatic nervous systems, and the organization of the vertebrate nervous system. It is based on lectures by Brian Allison Martos on March 19 and April 11, 2024.
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