Human Circulatory System Quiz

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Questions and Answers

What primary factor decreases pulmonary compliance?

Decreased lung elasticity

Increased airway resistance

Increased alveolar surface tension (correct)

Decreased chest wall movement

During inspiration, how does airway resistance change?

Increases due to lung recoil

Fluctuates randomly without a pattern

Remains constant throughout ventilation

Decreases as airways are pulled open (correct)

What impact does restrictive lung disease have on pulmonary compliance?

It leads to an increase in airway size and function

It decreases pulmonary compliance and effectiveness of inspiration (correct)

It increases pulmonary compliance and ease of breathing

It has no impact on pulmonary compliance

Which factor is NOT associated with decreased pulmonary compliance?

Increased chest wall flexibility Signup and view all the answers

What is the relationship defined by Boyle's Law in the context of pulmonary ventilation?

Pressure and volume are inversely proportional Signup and view all the answers

How does the role of the chest wall impact pulmonary compliance?

It helps facilitate the movement and stretch of the lungs Signup and view all the answers

What happens in the alveoli during expiration in relation to airway resistance?

Resistance increases due to lung recoil Signup and view all the answers

Which of the following is a characteristic of obstructive lung disease?

Increases airway resistance Signup and view all the answers

What is the primary function of veins in the circulatory system?

To collect oxygen-poor blood and return it to the heart Signup and view all the answers

Which blood vessel carries oxygenated blood from the placenta to the fetus?

Umbilical Vein Signup and view all the answers

What is the formula for calculating Mean Arterial Pressure (MAP)?

MAP = diastolic BP + (systolic - diastolic) / 3 Signup and view all the answers

Which of the following structures allows most blood to flow from the right atrium to the left atrium in fetal circulation?

Foramen Ovale Signup and view all the answers

What primarily causes damage to arteries in arteriosclerosis?

High cholesterol and high blood pressure Signup and view all the answers

What role does the sympathetic nervous system play in heart function?

It increases heart rate by releasing catecholamines Signup and view all the answers

In the process of oxygen exchange, what are the capillaries primarily responsible for?

Facilitating the exchange of oxygen, nutrients, and waste with tissues Signup and view all the answers

How does blood flow through the circulatory system?

From areas of higher pressure to areas of lower pressure Signup and view all the answers

What is the main function of alveolar type II cells?

Produce pulmonary surfactant Signup and view all the answers

What is the role of pulmonary surfactant in lung function?

Decreases surface tension in alveoli Signup and view all the answers

What happens to intrapulmonary pressure during expiration?

It increases as lung volume decreases Signup and view all the answers

What is the primary effect of vasodilation caused by atrial natriuretic peptide?

Decrease blood pressure Signup and view all the answers

How does angiotensin II primarily affect blood pressure?

Causes vasoconstriction Signup and view all the answers

What structural feature of the bronchi differs between the right and left lung?

Number of secondary bronchi Signup and view all the answers

What change occurs in the pleural cavity during inspiration?

Volume expands and pressure decreases Signup and view all the answers

What condition can result from uncontrolled hypertension?

Heart disease Signup and view all the answers

Study Notes

Layers of Arteries and Veins

Tunica intima: Innermost layer, made of endothelial cells lining the vessel lumen
Tunica media: Middle layer, made of smooth muscle cells and connective tissue
Tunica adventitia (external): Outermost layer, made of connective tissue anchoring the vessel to surrounding tissues

Comparison of Arteries and Veins

Arteries: Thicker tunica media, more extensive internal and external elastic lamina, thicker, more elastic fibers, smaller lumens, no valves, less arteries than veins
Veins: Thinner tunica media, less extensive internal and external elastic lamina, thinner, fewer elastic fibers, larger lumens, venous valves, more veins than arteries

Veins

Veins are blood vessels that collect oxygen-poor blood and return it to the heart
They work with other blood vessels and the heart to keep blood moving
Veins hold most of the blood in the body

Capillaries

Capillaries are the smallest blood vessels in the body
They form a network that connects arteries to veins
Their thin walls allow for the exchange of oxygen, nutrients, and waste products between the blood and tissues

Fetal Circulation

Oxygenated blood is carried from the placenta to the fetus through the umbilical vein
Half of the blood passes through the hepatic capillaries (liver), and the rest flows through the ductus venosus to the inferior vena cava

Blood Flow

Blood flows from an area of higher pressure to an area of lower pressure
Vena cava: Deoxygenated blood enters the heart through the superior and inferior vena cava
Right atrium: Blood flows into the right atrium
Tricuspid valve: Blood passes through the tricuspid valve into the right ventricle
Right ventricle: The right ventricle pumps blood through the pulmonary valve
Pulmonary valve: Blood exits the right ventricle through the pulmonary valve
Pulmonary artery: Blood travels to the lungs via the pulmonary artery

Lungs

In the lungs, blood picks up oxygen
Pulmonary veins: Oxygenated blood returns to the heart via the pulmonary veins
Left atrium: Blood enters the left atrium
Mitral valve: Blood flows through the mitral valve into the left ventricle
Left ventricle: The left ventricle pumps blood through the aortic valve
Aortic valve: Blood exits the left ventricle through the aortic valve
Aorta: Blood travels throughout the body through the aorta

Atherosclerosis

A type of vascular disease where blood vessels (arteries) carrying oxygen away from the heart become damaged
Factors include high cholesterol, high blood pressure, diabetes, and certain genetic influences

Mean Arterial Pressure (MAP)

The average blood pressure in an individual's arteries during a cardiac cycle
MAP = diastolic BP + (systolic - diastolic) / 3

Peripheral Nervous System Stimulation

Sympathetic nervous system (SNS): Releases catecholamines (epinephrine and norepinephrine) to increase heart rate
Parasympathetic nervous system (PNS): Releases acetylcholine to slow heart rate

Hormonal Influences on Blood Volume

The renin-angiotensin-aldosterone system (RAAS) regulates blood pressure and blood volume
Angiotensin II: Stimulates thirst and sodium retention, increasing blood volume
Atrial natriuretic peptide: Vasodilation to decrease peripheral resistance and blood pressure

Complications of Hypertension

If untreated, hypertension can cause kidney disease, heart disease, and stroke
Symptoms include severe headaches and chest pain

Lining of Nasopharynx

Pseudostratified columnar ciliated epithelium

Bronchial Tree

Branching structure of the airways, carrying air from the environment to the lungs for gas exchange
3 secondary bronchi in the right lung, and 2 in the left, due to space needed for the heart

Alveolar Cells

Specialized cells lining the alveoli of the lungs, where gas exchange occurs
Two main types: Type I and Type II
Type I alveolar cells: Simple squamous, compose 90% of the alveolar wall, thin for rapid diffusion
Type II alveolar cells: Cuboidal, compose 10%, produce surfactant to decrease surface tension
Alveolar macrophages: Phagocytes of the alveolar surface

Pressure within Pleural Cavity

Maintains a negative pressure
During inspiration, volume expands, intrapleural pressure drops, and intrapulmonary pressure drops, expanding lungs and drawing air in
During expiration, this process reverses

Pulmonary Ventilation

Made up of two main steps: Inspiration and expiration
Airway resistance: Decreases during inspiration as airways open
Alveolar surface tension: Increases during expiration as lung recoil and airways narrow
Pulmonary compliance: Ability of the lung and chest wall to stretch

Pulmonary Volumes and Capacities

Tidal volume (TV): Air inhaled or exhaled during a normal breath
Inspiratory reserve volume (IRV): Additional air inhaled after a normal inhalation
Expiratory reserve volume (ERV): Additional air exhaled after a normal exhalation
Residual volume (RV): Air remaining in the lungs after a maximal exhalation
Inspiratory capacity (IC): Max amount of air inspired after a normal exhalation
Functional residual capacity (FRC): Amount of air remaining in the lungs after a normal exhalation
Vital capacity (VC): Max amount of air exhaled after a maximal inhalation
Total lung capacity (TLC): Total volume of air the lungs can hold

Pulmonary Compliance Factors

Degree of alveolar surface tension
Distensibility of lung elastic tissue
Ability of chest wall to move

Disorders of Respiratory System

Obstructive lung diseases: Increase airway resistance, decrease efficiency of expiration (Emphysema, chronic bronchitis, asthma)
Restrictive lung disease: Decrease pulmonary compliance, decrease efficiency of inspiration

Systemic Circulation

High pressure in the left ventricle and aorta drives blood through the arteries to capillaries.
Low pressure in veins and right atrium allows blood to return to heart.

Pulmonary Circulation

Blood flows from the right ventricle through pulmonary arteries (high pressue) into pulmonary capillaries (lower pressure) for gas exchange
Oxygenated blood returns to left atrium via pulmonary veins

Boyle's Law

Pressure and volume are inversely proportional

Henry's Law

Amount of dissolved gas is directly proportional to its partial pressure and its solubility in the liquid

Dalton's Law

The total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases

Baroreceptors

Detect blood pressure

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Description

Test your knowledge on the layers of arteries and veins, their differences, and the function of capillaries in the human circulatory system. This quiz covers fundamental concepts in vascular biology, helping you understand how blood vessels operate and their role in our body.