HBS: Unit 3 Test Prep

Pulmonary circulation

Flow of oxygen-poor blood from the right side of the heart to the lungs and back to the left side as oxygen-rich blood

Systemic circulation

Flow of oxygen-rich blood from the left side of the heart to the body and back to the right side as oxygen-poor blood

Blood entering heart from body

Superior and inferior vena cava carry oxygen-poor blood into the right atrium

Right atrium to right ventricle

Blood passes through the tricuspid valve

Right ventricle to lungs

Blood passes through the pulmonary valve into the pulmonary artery

Pulmonary artery

Carries oxygen-poor blood to the lungs

Lungs

Release CO2 and pick up O2

Blood returning from lungs

Pulmonary veins carry oxygen-rich blood to the left atrium

Left atrium to left ventricle

Blood passes through the mitral valve

Left ventricle to body

Blood passes through the aortic valve into the aorta

Aorta

Distributes oxygen-rich blood to the body

Pathway of Blood

Blood returning from the body enters the heart through the superior and inferior vena cava. These large veins carry oxygen poor blood into the right atrium. From the right atrium, blood passes through the tricuspid valve into the right ventricle. When the right ventricle contracts,  blood is pushed through the pulmonary valve and into the pulmonary artery. The pulmonary artery carries this oxygen-poor blood into the  lungs,  where CO2 is released and O2 is picked. After becoming oxygen-rich, the blood returns to the heart through the pulmonary veins,  which empty into the left atrium.  Blood then flows through the mitral valve into the left ventricle.  When the left ventricle contracts,  it sends blood through the aortic valve into the aorta. The aorta distributes the oxygen rich blood into the body,  and the cycle repeats.

Arteries

Thick, muscular walls for high-pressure blood flow away from the heart

Veins

Thinner walls with valves; carry blood back to the heart under lower pressure

Capillaries

Tiny vessels with one-cell-thick walls for exchange of nutrients and wastes

Systolic pressure

Pressure generated by the left ventricle during contraction

Diastolic pressure

Pressure in the arteries between heartbeats, when the heart is relaxed

Normal blood pressure

Less than 120 systolic and less than 80 diastolic

Elevated blood pressure

120–129 systolic and less than 80 diastolic

Stage 1 hypertension

130–139 systolic or 80–89 diastolic

Stage 2 hypertension

140 or higher systolic or 90 or higher diastolic

Hypertensive crisis

Higher than 180 systolic and/or higher than 120 diastolic

Cardiac output

A measure of how much blood is pumped by both ventricles in one minute

Cardiac output formula

CO = Heart Rate × Stroke Volume

Normal resting stroke volume

About 55–100 mL per beat

Why cardiac output matters

Shows heart strength, efficiency, and ability to meet oxygen demands

Increased cardiac output

Increases oxygen delivery to tissues

Decreased cardiac output

Can cause fatigue, confusion, and organ failure from reduced tissue perfusion and oxygen supply

PAD

Peripheral artery disease; caused by reduced blood flow to the extremities

PAD risks

Smoking, uncontrolled diabetes, high blood pressure, high cholesterol

PAD complication

Increased risk of clots and blocked blood flow to limbs

ABI (Ankle Brachial Index)

Indicates PAD.
Lower ankle-brachial index means more severe PAD

Cardiac Output

Elevated resting heart rate can indicate cardiovascular strain
Cardiac output is not helpful in determining PAD

Heart conduction pathway

SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers

Heart Conduction System

Specialized network of cardiac muscle cells that initiates and transmits electrical impulses, ensuring heartbeat

SA node

Heart’s natural pacemaker in the right atrium, generates electrical impulses to start the heartbeat.

AV node

Located between the atria and ventricles, delays signal so ventricles can fill with. blood before contracting

Bundle of His

A bundle of fibers that receives the signal from the AV node and carries towards ventricles.

Purkinje fibers

Specialized fibers that rapidly spread the electrical impulse throughout the ventricles, causing them to contract and pump blood out to the body.

Arrhythmia

Funky heart rhythm

Bradyarrhythmia (Funky Heart Rhythm)

Heart rate less than 60 BPM

Tachyarrhythmia (Funky Heart Rhythm)

Heart rate greater than 100 BPM

Pacemaker

Implanted device that corrects irregular heart rhythm

Pacemaker function

Corrects bradycardia and helps prevent fatigue, dizziness, and fainting

Trachea

Carries air from throat to lungs

Lungs

Bring oxygen into blood and remove CO2

Larynx

Allows speech and helps keep airway open

Pharynx

Passageway that moves air from nose and mouth to larynx

Nasal cavity

Filters, warms, and moistens incoming air

Bronchi

Carry air from trachea to each lung

Bronchioles

Move air deeper into lungs toward alveoli

Alveoli

Tiny air sacs where gas exchange occurs

Epiglottis

Prevents food from entering airway during swallowing

Diaphragm

Main muscle that helps breathing by contracting and relaxing

Respiratory zone

Where O2 and CO2 exchange occurs

Respiratory zone structures

Bronchioles and alveoli

Conducting zone

Transports air to and from lungs

Conducting zone structures

Nose, pharynx, larynx, trachea, bronchi

Breathing pathway

Nose/oral cavity → pharynx → larynx → trachea → bronchi → bronchioles → alveoli

How do we breathe?

People breathe by receiving air from their noses and oral cavities
Pharanx (epiglottis) -> larynx (air) -> trachea -> R/L bronchi -> bronchiole -> alveoli

Gas exchange

O2 moves from lungs into blood; CO2 moves from blood into lungs to be exhaled

Right lung

Superior, middle, and inferior lobes; horizontal fissure

Left lung

Superior and inferior lobes; oblique fissure

Lungs before inflation

More pink and less elastic

Lungs after inflation

Lighter and tissue stretched out

Asthma

Chronic lung disease causing airway inflammation, narrowing, and excess mucus

Asthma symptoms

Wheezing, coughing, chest tightness, shortness of breath

Albuterol

Rescue medication for asthma

Fluticasone

Long-term medication to prevent asthma symptoms

Bacteria

Single-celled, living prokaryotes that can cause infections

Bacteria example

Strep throat

Viruses

Nonliving particles of genetic material that need a host cell to reproduce

Virus effect

Destroy host cells and take over protein synthesis

Virus example

Flu

Protists

Cause tissue and organ damage and deprive hosts of nutrients

Protist example

Giardiasis

Fungi

Can cause tissue damage as spores reproduce heavily

Fungi example

Athlete’s foot

Epidermis

Top layer of skin

Epidermis traits

Not sensitive or vascular

Keratin (Epidermis)

Fibrous protein that is the main component of hair

Dermis

Sensitive skin layer below epidermis

Collagen and elastin

Dermis proteins that give skin smooth and youthful structure

Hypodermis

Layer below skin

Hypodermis contents

Fat tissue, blood vessels, connective tissue

Sweat glands

Begin in the superficial hypodermis and extend through the dermis and empty out of the epidermis.

Sebaceous glands

Begin in the hypodermis and empty through pores in the epidermis.

Sebum (Sebaceous glands)

Oily/waxy material that lubricates and waterproofs skin and hair

Arrector pili muscle

Accessory skin structure

Sepsis

Immune system overreacts to infection and causes inflammation

Severe sepsis

Organs malfunction, blood pressure drops, inflammation continues

Septic shock

Extremely low blood pressure that does not respond to IV fluids

T in TIME

Higher or lower than normal temperature

I in TIME

Signs and symptoms of infection

M in TIME

Mental decline; confused, sleepy, or hard to rouse

E in TIME

Extremely ill; severe pain or discomfort

Lymphatic system role

Transports lymph and maintains fluid levels in the body

Lymphatic system structures

Organs, ducts, and lymph nodes

Lymph nodes

Rounded masses of lymphoid tissue surrounded by connective tissue capsule

Lymph

Clear fluid that passes into lymphatic vessels