Zoology 120: Animal Physiology - Peripheral Nervous System

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Questions and Answers

What is the primary function of the blood-nerve barrier?

To innervate the spinal cord
To allow the passage of molecules
To maintain the fiber's environment (correct)
To classify nerve fibers

What type of nerve fiber innervates the brain?

Cranial nerve (correct)
Spinal nerve
Collateral ganglion
Terminal ganglion

What is the main component of the peripheral nervous system?

Central nervous system
Nerves (correct)
Ganglia
Axons

What is the purpose of the endoneurium?

To cover the axon and myelin sheath (A) Signup and view all the answers

What type of ganglion is composed of cell bodies of nerve fibers?

Any of the above (D) Signup and view all the answers

What is the function of the perineurium?

To surround bundles of axons (A) Signup and view all the answers

What is the classification of a nerve fiber that innervates the spinal cord?

Spinal nerve (A) Signup and view all the answers

What is found in the endoneurium besides axons?

Reticular fibers, scattered fibroblasts, capillaries, and occasional mast cells and macrophages (D) Signup and view all the answers

What is the primary factor that determines the flow of blood in capillaries?

The flow of blood from arterioles (B) Signup and view all the answers

What is the function of sweat glands during stressful situations?

To reduce heat (D) Signup and view all the answers

What is the effect of sympathetic stimulation on salivary glands?

Decreases salivary secretion (B) Signup and view all the answers

What is the relationship between the sympathetic and parasympathetic nervous systems in salivary glands?

Synergistic (A) Signup and view all the answers

Which of the following nervous systems is responsible for the 'fight or flight' response?

Sympathetic nervous system (D) Signup and view all the answers

What is the effect of parasympathetic stimulation on salivary glands?

Increases salivary secretion (C) Signup and view all the answers

What is the primary function of the sympathetic nervous system in arterioles?

To constrict arterioles (A) Signup and view all the answers

What is the relationship between the sympathetic and parasympathetic nervous systems in terms of their functions?

Antagonistic (A) Signup and view all the answers

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 (C) Signup and view all the answers

What type of stimuli can afferent neurons receive?

Either sensory or visceral stimuli (C) Signup and view all the answers

What is the primary function of the sympathetic nervous system in emergency situations?

To promote responses that prepare the body for strenuous physical activity (C) Signup and view all the answers

Which type of glands are innervated by only the sympathetic nervous system?

Sweat glands (B) Signup and view all the answers

What is the characteristic of the dual innervation of organs by both sympathetic and parasympathetic fibers?

It produces opposite effects in a particular organ (B) Signup and view all the answers

What is the location of the enteric nervous system?

Within the wall of the digestive tract (B) Signup and view all the answers

What is the direction of travel of afferent fibers compared to efferent fibers?

In the opposite direction (D) Signup and view all the answers

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 (D) Signup and view all the answers

What type of receptors are activated by nicotine and can be found on postganglionic cell bodies of all autonomic ganglia?

Nicotinic Receptors (B) Signup and view all the answers

What is the result of IP3 binding to a receptor in the sarcoplasmic reticulum?

Opening of the Ca2+ channel (A) Signup and view all the answers

What is the effect of NE binding to an alpha receptor?

Activation of phospholipase C (A) Signup and view all the answers

What is the function of muscarinic receptors in the heart?

Decrease the rate of contraction (B) Signup and view all the answers

What is the effect of ACh on the heart when it binds to a muscarinic receptor?

Decrease the rate of contraction (D) Signup and view all the answers

What is the mechanism of action of Metoprolol?

Blocks beta1-adrenergic receptors (D) Signup and view all the answers

What is the effect of Salbutamol on the bronchioles?

Dilation of the bronchioles (A) Signup and view all the answers

What is the primary mechanism involved in the activation of β1 adrenergic receptor?

G protein-coupled mechanism (C) Signup and view all the answers

What is the effect of phosphorylation of sarcoplasmic reticulum receptors in the heart?

Increased release of Ca2+ ions (D) Signup and view all the answers

Which region of the CNS is NOT involved in the control of skeletal muscle activity?

Occipital lobe (D) Signup and view all the answers

What is the effect of Ca2+ ion binding to troponin in the heart?

Increased actin-myosin interaction (C) Signup and view all the answers

What is the primary neurotransmitter released by motor neurons at the neuromuscular junction?

Acetylcholine (B) Signup and view all the answers

What is the effect of activation of protein kinase in the heart?

Phosphorylation of sarcoplasmic reticulum receptors (C) Signup and view all the answers

What is the characteristic of the motor end plate at the neuromuscular junction?

Has no threshold potential (C) Signup and view all the answers

What is the term for the progressive degeneration of motor neurons, as seen in Lou Gehrig's disease?

Amyotrophic Lateral Sclerosis (ALS) (C) Signup and view all the answers

What is the purpose of the perineurium in the peripheral nervous system?

To form the blood-nerve barrier and prevent the passage of molecules (B) Signup and view all the answers

What is the classification of a nerve fiber that comes from the brain?

Cranial nerve (C) Signup and view all the answers

What is the function of the endoneurium in the peripheral nervous system?

To surround individual axons and maintain their environment (C) Signup and view all the answers

What is the term for the bundles of axons in the peripheral nervous system?

Fascicles (B) Signup and view all the answers

What is the term for the cell bodies of neurons outside the central nervous system?

Ganglia (A) Signup and view all the answers

What is the purpose of the reticular fibers in the endoneurium?

To provide structural support to the nerve fibers (D) Signup and view all the answers

What is the type of connective tissue found in the outermost covering of a nerve?

Dense irregular connective tissue (A) Signup and view all the answers

What is the term for the blood vessels found in the epineurium?

Arteries and veins (B) Signup and view all the answers

What is the function of mast cells and macrophages in the nervous system?

To kill microorganisms that enter the axons (D) Signup and view all the answers

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 (C) Signup and view all the answers

What is the location of capillaries in a nerve?

In each fascicle (A) Signup and view all the answers

What is the shape of arteries compared to veins in the epineurium?

Arteries are more circular, while veins are more flat (C) Signup and view all the answers

Which type of neuron is responsible for integrating afferent information and formulating an efferent response?

Interneuron (C) Signup and view all the answers

What is the direction of travel of the signal in an afferent fiber?

From the receptor to the CNS (B) Signup and view all the answers

What is the site of release of neurotransmitters in an efferent neuron?

Axon terminal (C) Signup and view all the answers

Which part of the neuron receives the signal from the afferent neuron?

Dendrites (C) Signup and view all the answers

What is the function of the axon terminal of the efferent neuron?

To transmit the signal to the effector organ (C) Signup and view all the answers

What is the site of integration of afferent information?

Interneuron (C) Signup and view all the answers

What is the primary characteristic of the cell bodies in sensory ganglia?

They are pseudounipolar neurons (A) Signup and view all the answers

What is the function of the satellite glial cells in ganglia?

They provide nutrition to the neurons (D) Signup and view all the answers

What is the characteristic of lipofuscin in ganglia?

It is a pigment that increases with age (C) Signup and view all the answers

What is the difference between sensory ganglia and autonomic ganglia?

Sensory ganglia have a more distinct capsule (B) Signup and view all the answers

What is the characteristic of the efferent nerve pathways in the autonomic nervous system?

They consist of a two-neuron chain (A) Signup and view all the answers

What is the type of neuron found in autonomic ganglia?

Multipolar neurons (C) Signup and view all the answers

What is the primary function of the adrenal cortex?

To secrete glucocorticoids essential for metabolism (A) Signup and view all the answers

What is the effect of alpha 1 receptors on arterioles?

Constriction (C) Signup and view all the answers

What is the primary messenger system used by beta 1 receptors?

cAMP (A) Signup and view all the answers

Which type of receptors have a greater sensitivity towards norepinephrine?

Alpha 1 receptors (B) Signup and view all the answers

What is the effect of beta 2 receptors on bronchioles?

Dilation (A) Signup and view all the answers

Which type of receptors are inhibitory, and found mainly in the smooth muscles of the digestive tract?

Alpha 2 receptors (A) Signup and view all the answers

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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

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