Physiology Chapter on Nervous System and Cardiac Cycle

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Questions and Answers

What are the two main components of the central nervous system?

Cerebellum and brainstem

Brain and cranial nerves

Brain and spinal cord (correct)

Spinal cord and peripheral nerves

Which division of the nervous system carries motor commands from the CNS to peripheral tissues?

Central processing unit

Autonomic division

Peripheral nervous system (correct)

Sympathetic division

What type of function is NOT attributed to the central nervous system?

Controlling voluntary muscle movement

Providing sensory information (correct)

Issuing motor commands

Integrating sensory data

The autonomic division of the motor system controls which type of muscle?

Involuntary muscles Signup and view all the answers

Which of the following is NOT a higher function of the central nervous system?

Speed of reflexes Signup and view all the answers

What is the function of the perineurium in a peripheral nerve?

It forms a barrier that controls access of materials to nerve tissue. Signup and view all the answers

Which of the following correctly describes the composition of peripheral nerves?

They contain both myelinated and unmyelinated nerve fibers. Signup and view all the answers

What is the duration of one complete cardiac cycle at rest?

0.65 seconds Signup and view all the answers

Which component of the peripheral nerve is responsible for the rapid conduction of nerve impulses?

Node of Ranvier Signup and view all the answers

What role do Schwann cells play in the structure of peripheral nerves?

They form the myelin sheath around the axon. Signup and view all the answers

What is the formula for calculating cardiac output?

Cardiac output = heart rate x stroke volume Signup and view all the answers

What would be the cardiac output per minute for a person with a heart rate of 72 bpm and a stroke volume of 70 mL?

5040 mL Signup and view all the answers

How many pairs of cranial nerves are responsible for innervating the sense organs, muscles, and glands?

12 pairs Signup and view all the answers

What types of information do cranial nerves carry?

Motor, sensory, and autonomic information Signup and view all the answers

During which phase of the cardiac cycle are both atria and ventricles in a relaxed state?

Diastole Signup and view all the answers

What is the average stroke volume of a person at rest?

70 mL Signup and view all the answers

Which layer of the nerve provides the outermost protective covering?

Epineurium Signup and view all the answers

Which structure is specifically identified by its reticular fibers as seen in a transverse section?

Endoneurium Signup and view all the answers

Which of the following correctly describes the pathway of oxygenated blood returning from the lungs to the heart?

Pulmonary veins → Left atrium → Bicuspid valve → Left ventricle Signup and view all the answers

In terms of heart rate, which value represents the average heart rate of a person at rest?

70 beats per minute Signup and view all the answers

What is the measurement of cardiac output typically reported in?

Milliliters per minute Signup and view all the answers

What type of cranial nerves carry afferent information from the special senses?

Special sensory Signup and view all the answers

Which classification of cranial nerves carries efferent information to skeletal muscles?

Somatomotor Signup and view all the answers

How many pairs of spinal nerves emerge between each vertebra from the spinal cord?

31 pairs Signup and view all the answers

Which pair has the highest number of spinal nerves?

Cervical pairs Signup and view all the answers

Which of the following does NOT describe spinal nerves?

They are part of the central nervous system. Signup and view all the answers

Which spinal nerve segment corresponds to the third cervical vertebra?

C3 Signup and view all the answers

Which of the following autonomic effectors does autonomic motor cranial nerves primarily target?

Smooth muscles Signup and view all the answers

Which pairs of spinal nerves are found in the lumbar region?

5 pairs Signup and view all the answers

How many spinal segments are there?

31 Signup and view all the answers

What type of fibers does the dorsal root of a spinal nerve primarily contain?

Afferent fibers Signup and view all the answers

Which of the following is true regarding the ventral root of a spinal nerve?

It mainly contains motor fibers. Signup and view all the answers

Which component of the spinal nerve does not contain a ganglion?

Ventral root Signup and view all the answers

Why is knowledge of segmental innervation important?

To diagnose site of an injury Signup and view all the answers

Which of the following best describes spinal nerves?

Mixed nerves Signup and view all the answers

What is a characteristic of the dorsal root ganglion?

Contains sensory neuron cell bodies Signup and view all the answers

How do spinal nerves connect to the spinal cord?

Through both the dorsal and ventral roots Signup and view all the answers

What is the primary role of the dorsal ramus?

Supplies the muscles and skin of the back Signup and view all the answers

Which ramus is larger and passes anterolaterally?

Ventral ramus Signup and view all the answers

What is formed when the ventral rami of several spinal nerves join at the roots of the limbs?

Nerve plexus Signup and view all the answers

What is a consequence of the formation of nerve plexuses?

It allows for redundant control of muscle movement Signup and view all the answers

Which segments of the spinal cord contribute to the control of muscle movement in a limb?

Several segments contribute through nerve plexuses Signup and view all the answers

Which part of the body does the ventral ramus supply?

The side and front of the body, including limbs Signup and view all the answers

What type of fibers does each spinal nerve's dorsal and ventral rami contain?

Both motor and sensory fibers Signup and view all the answers

What significant advantage does the arrangement of nerve plexuses provide?

Nerve plexuses ensure redundancy and coordination among multiple spinal nerves Signup and view all the answers

Study Notes

Human Anatomy and Physiology - Week 5

The heart muscle cell is myogenic, meaning it generates and conducts impulses automatically.
This coordination allows the contraction of atria and ventricles.
The sinoatrial (SA) node is the heart's pacemaker, located in the right atrium.
Electrical impulses from the SA node spread through both atria, causing them to contract.
The atrioventricular (AV) node receives these impulses, delaying them slightly.
The AV node sends the impulses down the septum through the Bundle of His, which contains Purkinje fibers.
The impulse then causes ventricular contraction.
Arrhythmias can be treated with pacemakers, which are small devices that use electrical pulses to regulate heart rate.

ECG (Electrocardiogram)

An ECG records the electrical activity of the heart over time.
Electrodes are placed on the skin to detect these electrical signals.
A normal ECG trace has distinct waves:
- P wave: atrial contraction
- QRS complex: ventricular contraction
- T wave: ventricular relaxation
Heart defects can produce modified ECG traces.

Cardiac Cycle

A cardiac cycle is the sequence of events in one heartbeat.
A resting heart cycle lasts about 0.8 seconds (75 beats per minute).
The cardiac cycle involves atrial and ventricular systole (contraction) and diastole (relaxation)
Atria work together and ventricles work together in a coordinated manner.
Heart pressures will change along with blood volume in a coordinated way.
Aortic and Auricular pressure change during a single cardiac cycle.
The cycle is regulated by several components.

Nervous System Organisation

The nervous system consists of the central nervous system (CNS) and peripheral nervous system (PNS).
CNS includes the brain and spinal cord.
PNS includes nerves and ganglia.
The PNS is further divided into sensory and motor systems.
- Somatic Nervous System controls voluntary muscles.
- Autonomic Nervous System regulates involuntary functions (e.g., smooth muscle, glands).
  - Sympathetic Nervous System: "Fight or Flight"
  - Parasympathetic Nervous System: Rest and Digest".

Cellular Components of the Nervous System

Neurons are the fundamental units of the nervous system.
They transmit signals using electrical and chemical signals.
Glial cells support and protect neurons, contributing to their function
- Ependymal cells: Produce cerebrospinal fluid.
- Microglia: Immune defence.
- Oligodendrocytes: Produce myelin in the CNS.
- Schwann cells: Produce myelin in the PNS.
- Astrocytes: Support, nourish, and protect neurons in the CNS
Nerve cells and nerve fibers are typically very long-lived/amiotic

Peripheral Nerve Structure

Peripheral nerves consist of bundles (fascicles) of nerve fibers
- axons of neurons of the PNS, which may be sensory (afferent), motor (efferent), somatic, or automatic.
Myelin sheath insulates axons, increasing the speed of signal transmission.
Myelin is produced by glial cells (oligodendrocytes in CNS, Schwann cells in PNS).

Cranial Nerves

12 pairs of cranial nerves emerge from the brain.
Cranial nerves have various functions, including sensory (smell, vision, taste), motor (eye movement, facial expression), and mixed functions (sensory and motor).

Spinal Nerves

31 pairs of spinal nerves emerge from the spinal cord, with different named parts involved to relay information to specific body parts.
Each segment of the spinal cord corresponds to a segment of nerves, related to specific body regions.
Spinal nerves emerge between vertebrae, as specified by letter and number.

Cardiac Output

Cardiac output measures the amount of blood pumped by the heart per minute.
It is calculated by multiplying heart rate by stroke volume.
Hormones can influence heart rate and strength of contraction.
Venous return and heart muscle strength are important factors for stroke volume.

Stroke Volume

Stroke volume is the amount of blood the heart pumps per beat.
Factors influencing stroke volume include venous return, contractility of the heart muscle, and heart rate.

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Description

This quiz assesses your understanding of the central nervous system and the cardiac cycle, covering key components, functions, and measurements. Test your knowledge on topics such as peripheral nerves, cardiac output, and the roles of specific cells like Schwann cells. Ideal for students studying physiology or related fields.