Human Physiology Quiz on Cardiac Function

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Questions and Answers

What does the sympathetic nervous system primarily increase during stressful situations?

Heart rate (correct)

Blood flow to digestion

Carbon dioxide levels

Oxygen levels in the brain

What causes the medulla oblongata to stimulate an increase in heart rate during exercise?

High blood pressure

Increase in carbon dioxide levels (correct)

Increase in blood sugar

Low oxygen levels

What condition is characterized by the buildup of fatty materials inside the arteries?

Hypertension

Cardiac arrest

Angina

Atherosclerosis (correct)

What is the primary effect of a heart attack on the heart tissue?

It results in a lack of oxygen Signup and view all the answers

What is the major consequence of a stroke?

Weakness on one side of the body Signup and view all the answers

Which factor is known to increase heart rate by the release of hormones?

Adrenaline Signup and view all the answers

What happens to heart tissue after about four minutes of significant blood flow loss?

Tissue damage becomes significant Signup and view all the answers

What condition is described by chest pain due to poor blood circulation to the heart?

Angina Signup and view all the answers

What is the primary function of the sinoatrial (SA) node in the heart?

It sets the pace for heartbeats. Signup and view all the answers

How do the Purkinje fibers contribute to heart function?

They help transmit nerve impulses to cause ventricular contraction. Signup and view all the answers

What occurs if the sinoatrial (SA) node is not functioning properly?

An artificial pacemaker may be needed. Signup and view all the answers

Which nervous system component increases heart rate and cardiac output?

Sympathetic nervous system Signup and view all the answers

What is the role of the atrioventricular (AV) node in the cardiac conduction system?

It connects the atria to the ventricles. Signup and view all the answers

What is the primary function of red blood cells (RBCs)?

Carry O2 to tissues Signup and view all the answers

What regulates the heart rate in response to bodily needs?

Autonomic nervous system signals Signup and view all the answers

What percentage of blood is composed of plasma?

55% Signup and view all the answers

Which of the following components is NOT part of blood plasma?

Hemoglobin Signup and view all the answers

Which statement is true regarding cardiac muscle?

It contracts rhythmically due to electrical impulses. Signup and view all the answers

What initiates the clotting process when a blood vessel is injured?

Platelets releasing thromboplastin Signup and view all the answers

What is typically the resting heart rate established by the SA node?

70 beats per minute Signup and view all the answers

What is the relationship between blood pressure and body weight?

Higher body weight leads to increased blood pressure. Signup and view all the answers

What is the lifespan of a mature red blood cell?

120 days Signup and view all the answers

Which of the following steps can help in the prevention of high blood pressure?

Maintaining a healthy weight. Signup and view all the answers

Which component of blood is responsible for phagocytosis of invading cells?

Leukocytes Signup and view all the answers

Which of the following is the primary reason for the structure of red blood cells?

To increase surface area for gas exchange Signup and view all the answers

What happens to arteries as a person ages?

Arteries become hardened and less active. Signup and view all the answers

What differentiates white blood cells from red blood cells?

Presence of a nucleus Signup and view all the answers

What action should be taken before using a stethoscope?

Wipe the ear pieces with alcohol swabs. Signup and view all the answers

What effect does smoking have on blood pressure?

It injures blood vessel walls and raises blood pressure. Signup and view all the answers

What is a potential consequence of high blood pressure if left uncontrolled?

Increased likelihood of dementia. Signup and view all the answers

Which of these is not a factor that increases the risk of high blood pressure?

Healthy diet rich in fruits and vegetables. Signup and view all the answers

During a heart rate assessment, which activity could be done to increase heart rate for measurement?

Do 20 jumping jacks. Signup and view all the answers

What does systolic blood pressure measure?

The pressure when the heart beats Signup and view all the answers

What are common symptoms of low blood pressure?

Dizziness and fatigue Signup and view all the answers

What could be a risk of untreated high blood pressure?

Increased risk of strokes and heart attacks Signup and view all the answers

What tool is used to measure blood pressure?

Sphygmomanometer Signup and view all the answers

How is diastolic blood pressure defined?

Pressure while the heart is relaxed Signup and view all the answers

What can cause a person to be unaware of their high blood pressure?

It is often asymptomatic in many individuals Signup and view all the answers

What is the minimum inflation level the cuff should reach during measurement?

160 mmHg Signup and view all the answers

What is hypertension?

High blood pressure that increases the risk of heart-related issues Signup and view all the answers

What is the primary danger associated with an aneurysm?

It can rupture and cause instant death. Signup and view all the answers

What role do lymph nodes play in the lymphatic system?

They filter lymph for foreign particles. Signup and view all the answers

How does lymph fluid move through the lymphatic system?

By skeletal muscle contractions. Signup and view all the answers

Which of the following statements about blood composition is false?

White blood cells are more abundant than red blood cells. Signup and view all the answers

What component of the circulatory system is primarily responsible for returning lymph to the bloodstream?

Lymphatic ducts Signup and view all the answers

Which type of fluid is specifically referred to as lymph?

Fluid leaked from capillaries. Signup and view all the answers

What is the function of the SA Node in the heart?

It generates electrical impulses to initiate heartbeats. Signup and view all the answers

What is the primary function of the lymphatic system in relation to bacteria and proteins?

To filter out bacteria and proteins from extracellular fluid. Signup and view all the answers

Study Notes

Control of the Heart

Home is where the heart is.
Cardiac muscle (myogenic muscle) contracts without external stimulation.
Heart contractions are caused by electrical impulses from nodes within the heart.

Control of the Heartbeat

Cardiac muscle, unlike other muscles, doesn't require external stimulation to contract.
Heart contractions are due to electrical signals from two heart nodes.
The nodes are named the sinus node and atrioventricular node
The electrical impulses travel via various heart structures (bundle of His, right/left bundle branches, Purkinje fibers)
The sinoatrial (SA) node and the atrioventricular (AV) node are important in controlling the heartbeat.

Internal Control

The SA node (pacemaker), located in the right atrium, sets the heart's rhythm.
Nerve impulses travel from the SA node to other cardiac muscle cells via modified muscle tissues.
Cardiac muscle contracts automatically, producing electrical signals.
Approximate heart rate is 70 beats per minute, with 70mL of blood being pumped out per beat.
Heart rate starts with the contraction of the atria, which pushes blood into the ventricles

Atrioventricular Node (AV node)

The AV node picks up the electrical impulses from the SA node.
The impulses cause the ventricles to contract, pushing blood out to the lungs and body.
It passes nerve impulses along special fibers (Purkinje fibers) to initiate ventricular contractions.

Diastole and Systole

Diastole refers to the heart at rest.
Systole refers to the heart contracting to pump blood.
The SA and AV nodes are involved in controlling these phases of the heartbeat.

Heart Electrical Activity Summary

The images show the electrical signals moving through different parts of the heart (atria, ventricles, AV node, SA node) during diastole and systole via conducting fibers, for example, bundle branches and Purkinje fibers.
The sequence of activation can be seen in different images.

Artificial Pacemaker

An artificial pacemaker emits electrical signals to regulate the heartbeat if the SA node isn't functioning correctly.
Irregular heartbeat is called arrhythmia

External Control

Two nerves of the autonomic nervous system (sympathetic and parasympathetic) regulate heart rate.
Sympathetic nerves increase heart rate during stress (fight or flight response).
Parasympathetic nerves slow the heart rate during relaxation.
The medulla oblongata (part of the brain) responds to the body's needs by influencing the pacemaker (SA node) via nerve impulses.

Adjustment Due to Exercise

Increased carbon dioxide levels in the blood during exercise stimulate the medulla oblongata.
This triggers a nerve impulse to the SA node.
The increased heart rate moves blood to the lungs, removing excess carbon dioxide.

Other Factors Affecting Heart Rate

High temperature increases heart rate.
Hormones, such as adrenaline, also increase heart rate.

Disorders of the Circulatory System

Atherosclerosis is the buildup of fatty material inside arteries, which can cause the arteries to become hard.
This may cause high blood pressure, and/or rupture in arteries.
A blood clot may also form inside the arteries.
A heart attack occurs when blood flow to the heart is blocked, resulting in the death of heart muscle.
Angina is chest pain caused by reduced blood flow to the heart muscle.
Stroke occurs when a blood clot lodges in a blood vessel in the brain, or if a blood vessel ruptures. Tissues damage becomes significant after about 4 minutes, and can result in death or mental/physical problems

Embolus

A blood clot that dislodges inside a vessel, and later jams in another vessel.

Aneurysm

Aneurysms are due to a weak spot in an artery that causes a bulge in the artery wall.
If left untreated, may be extremely dangerous resulting in a rupture and instant death.

Lymphatic System

The lymphatic and circulatory systems are closely related; they interact and are similar to one another.
The lymphatic system returns extracellular fluid (containing protein and bacteria that leaked from capillaries) back to the circulatory system.
Lymph is fluid (containing protein) that leaks out of the capillaries.
Lymph flows through lymph vessels due to skeletal muscle contractions to prevent backflow (similar to veins).
Lymph nodes filter lymph for foreign particles, combating infections using white blood cells and phagocytosis.

Blood Structure and Function

Blood is made up of plasma, red blood cells (RBCs), white blood cells (WBCs), and platelets.
Plasma is about 55% of blood volume; RBCs about 44%; and WBCs & Platelets about 1%.
Plasma is mostly water, and includes proteins (like fibrinogen), glucose, vitamins, minerals, gases, and waste products.
RBCs carry oxygen to tissues and exchange with carbon dioxide for respiration. They are short lived (about 120 days) and contain hemoglobin to carry O₂. They have no nucleus when mature to maximize space for hemoglobin.
WBCs (leukocytes) combat infections through phagocytosis. They also produce antibodies for immunity. They are the largest of blood cells and each one has a nucleus.
Platelets play a critical role in blood clotting by secreting specialized proteins.

Blood Typing

There are four basic blood types (A, B, AB, O) determined by antigens on red blood cells.
Antibodies in blood plasma are made against other blood types and will clump (agglutinate) with their opposing antigen.
Blood typing is important for blood transfusions (avoiding clumping and blood blockages).

Rhesus (Rh) Factor

The Rh factor (another antigen) is present or absent on red blood cells.
Rh+ is present in about 85% of people.
Rh- is present in about 15% of people.
Humans do not naturally have Rh antibodies; an Rh- person can receive Rh+ blood in a transfusion.
Rh antibodies can be produced after an Rh- individual receives Rh+ blood in a transfusion, creating issues with blood clumping and blocking.

Rh and Pregnancy

If the mother is Rh- and the father is Rh+, the child might be Rh+.
If it's the first child, this is not an issue.
During birth, maternal and fetal blood mix.
The mother's immune system produces Rh+ antibodies.
The second child (if Rh+) will be attacked by antibodies from mother resulting in potentially fatal issues.

Erythroblastosis Fetalis

The condition occurs when a Rh- mother has an Rh+ second or subsequent child.
Mixing fetal and maternal blood during or after birth activates the mother's immune system, causing the production of Rh+ antibodies.
The antibodies attack the Rh+ fetal red blood cells, causing clumping and decreased oxygen delivery (resulting in a 'blue baby').
Transfusion of Rh- blood to the baby is the typical solution.

Sickle Cell Anemia

Sickle cell anemia is a genetic blood disorder.
In this condition, the hemoglobin is defective causing the red blood cells to become 'sickle-shaped', thus blocking blood flow through capillaries.
This can lead to numerous health issues.

Hemophilia

Hemophilia is a genetic condition wherein the ability to clot blood is affected.
It can be life-threatening as it can involve uncontrolled blood loss.
Transfusions can help address this problem and manage this condition.

Leukemia

Leukemia is a cancer of the white blood cells.
The number of WBCs increases, but the cells do not function normally.

Immunity

The immune system defends the body against pathogens (bacteria, viruses, fungi, and protozoa that can cause disease).
A series of physical (skin, stomach acid, cilia, mucous) and non-barrier (inflammation, antibody production) defenses protect against antigens.
The immune system can detect and fight invaders using antibodies and other immune response mechanisms.
Pathogens have marker proteins (antigens) that trigger antibody production when they enter the body.

Barrier Responses

Skin (layers of dead cells, oil, and sweat)
Digestive system (stomach acid, enzymes)
Gas exchange (hair, cilia, mucus, coughing, and sneezing)
Urinary system (mucus, periodic flow of urine)

Levels of Immune Protection

Innate response (physical barriers, phagocytic cells)
Acquired response (cellular and humoral responses, including memory immune responses)

Non-Barrier Responses

Inflammation is a response triggered when a pathogen enters the body.
Antibody production is the process by which antibodies are generated in the body in response to foreign antigens.

HIV

HIV (Human Immunodeficiency Virus) is a virus that can live in T-cells for days or even years, potentially not being active immediately.
Active HIV uses the helper T-cells' DNA to reproduce; when the helper T-cell bursts, HIV spreads to other T-cells.
HIV decimates T-cells, which can eventually lead to AIDS (Acquired Immunodeficiency Syndrome), wherein the immune system is poorly functioning.

Vaccines

Vaccines introduce a weakened or dead virus to the body to stimulate an immune response.
This helps the body develop antibodies to prepare the immune system for future infections by the same pathogen.
Second exposure to the antigen is met with a stronger and faster immune response due to memory cells.

Antibiotics

Antibiotics are medicines used to combat bacterial infections.
Overuse of antibiotics can lead to antibiotic-resistant bacteria, making treatment more difficult or impossible in the future.

Blood Sample Problems

Blood samples can be analyzed using different tests to determine if there are any abnormalities in the blood cell composition.
Common issues include low iron levels (anemia), high altitude, infection, heart disease, COPD, leukemia, and injury requiring clotting.

Blood Pressure

Blood pressure is the force exerted by the ventricles of the heart against the artery walls when they contract and relax.
Systolic pressure pertains to the heart pumping blood.
Diastolic pressure is the pressure when the heart is at rest between beats.
Increased blood pressure (hypertension) is associated with an elevated risk of strokes, heart attacks, and kidney failure, as well as dementia and sexual problems.
Low blood pressure (hypotension) can cause dizziness, fatigue and can cause organs like the heart, brain and kidneys to not receive enough blood.
Lab work involving blood pressure uses a cuff and stethoscope.

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Description

Test your knowledge of human physiology, focusing specifically on cardiac function and the nervous system's role in heart activity. This quiz covers the effects of stress, exercise, and various heart conditions. Perfect for students studying biology and physiology!