INTRO TO OXYGENATION Flashcards by michaela gail

functions of cardiovascular system

Delivers ___ and ___ to cells and tissues
Removes waste products ___ and ___
Pumps approximately ___ of blood
Approximately sized as a closed fist and weighs ___.

oxygen and nutrients
CO2 and metabolic products
5L/min
300g

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cardiac muscle layers

percardium
myocardium
endocardium

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outside and inner layer of the pericardium is called

outside - parietal
inner - visceral

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there is ___ml of fluid in the pericardial space

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Anchored by chordae tendineae
Open during relaxation, closed during ventricular contraction

atrioventricular valves

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2 AV valves

mitral and tricuspid

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Closed during relaxation, open during ventricular contraction

semilunar valves

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2 SL valves

pulmonary and aortic valves

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bring oxygen-rich blood from the aorta to the heart muscle (myocardium).

coronary arteries

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blood from coronary veins empties into the right atrium via the ___

coronary sinus.

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the heart muscle uses up most of the oxygen that the coronary arteries deliver — about ___%, which is a lot compared to other organs

70-80

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Most common area of atherosclerosis:

LMA (Left Main Artery) or LADA (Left Anterior Descending Artery)

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refer to the amount of pressure (or force) of blood inside the heart chambers and great vessels (like the aorta and pulmonary artery).

cardiac pressures

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the heart’s own electrical wiring that controls the heartbeat.

cardiac conduction system

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signals from within the heart’s conduction system itself.

increases conduction rate and ensures the heart beats as a unit.

Intrinsic conduction (nodal system)

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the heart can contract on its own — this ability is called

automaticity

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signals from outside the heart, like nerves (sympathetic and parasympathetic) or hormones (e.g., adrenaline)

extrinsic

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Function: Primary pacemaker — it starts the electrical impulse that triggers each heartbeat.

Normal rate: 60–100 impulses per minute

sinoatrial SA nodes

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Function: Secondary pacemaker, takes over only if the SA node fails. It also delays the signal slightly to let the atria finish contracting before the ventricles do.

Rate: 40–60 impulses per minute.

atrioventricular AV nodes

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Function: Conduct the electrical impulse throughout the ventricles, making them contract. They can act as a last-resort pacemaker if both the SA and AV nodes fail.

Rate: 30–40 impulses per minute.

bundle branch / purkinje fibers

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This is the electrical activation of the heart cell — the start of a heartbeat.

Sodium (Na⁺) ions rush into the cell, while potassium (K⁺) ions move out.

This makes the inside of the cell more positive, triggering the muscle to contract.

depolarization

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After depolarization, the cell must return to its resting state to prepare for the next beat.

During this phase, potassium (K⁺) moves back into the cell and sodium (Na⁺) moves out, restoring the normal balance and electrical charge.

repolarization

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These are times when heart cells cannot respond normally to another electrical signal.

refractory period

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During this brief time, even if a strong electrical impulse arrives, the cell is absolutely incapable of generating another action potential or contracting again.

This is crucial because it prevents the heart from going into a sustained, uncontrolled contraction, which would be fatal as it wouldn’t allow the ventricles to fill with blood.

effective refractory period

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During this time, the cell can be stimulated to generate another action potential, but it requires a much stronger-than-normal electrical impulse. it can sometimes trigger a dangerous, rapid, and uncoordinated heart rhythm (like ventricular fibrillation), as the heart is not fully ready for the next beat, leading to inefficient pumping.

relative refractory period

When the electrical impulse reaches the cardiac muscle cells (myocytes), it triggers ____ — the process that links the electrical signal to mechanical contraction.

excitation-contraction coupling

The influx of ___ during the action potential allows the muscle fibers to slide and shorten, causing the heart chambers to contract and pump blood.

calcium ions (Ca²⁺)

Refers to one complete heartbeat; series of pressure changes from blood movement.

cardiac cycle

average heartbeat

75 bpm, length of 0.8 seconds

Amount of blood pumped by the ventricles in liters per minute

cardiac output

normal CO

4-8 L/min

CO formula

CO = HR x SV

Refers to the degree of stretch of the heart muscle fibers at the end of diastole (when the ventricles are filled with blood).

preload

Describes the heart muscle’s ability to shorten and contract when stimulated by an electrical impulse.

contractility

The resistance the ventricles must overcome to eject blood during systole (contraction).

afterload

The percentage of blood that’s pumped out of the ventricle with each beat, compared to the total amount of blood in it at the end of diastole.

ejection fraction

blood functions

- transport gases, nutrients, waste products - regulate pH - maintain body temp - protect from foreign substances - clot formation

blood comprises ___% of total body weight

components of blood

plasma 55% formed elements 45%

cause blood from damaged vessels to clot

platelets

protect the body from infections, foreign proteins, and foreign bodies

wbc

carry o2 and co2. they contain a protein called hemoglobin which gives them a red color

rbc

helps form blood clots to halt bleeding. it is one of several coag factors

fibrinogen

maintained colloid osmotic pressure and transports some substances

albumin

help transport substances and determine an organisms immune properties

globulins

Take blood away from heart, thick/elastic walls, transport oxygenated blood, small lumen, pulse/spurts, no valves.

arteries

Take blood to heart, thin walls, transport de-oxygenated blood, large lumen, no pulse/smooth flow, has valves.

veins

A group of proteins in the blood that are essential for hemostasis, the process by which bleeding is stopped.

clotting factors

monitors warfarin and tests the extrinsic pathway

PT and INR

monitors heparin and tests the intrinsic pathway

PTT

gas exchange happens through the ___ in the lungs and body tissues

capillary walls

O2 diffuses from the capillary to ___

interstitial fluid.

Includes the nose, paranasal sinuses, turbinates, pharynx, tonsils and adenoids, and trachea. These structures filter, warm, and humidify the air before it reaches the lungs.

upper respi system

Includes the pleura (lining around the lungs), mediastinum (space between the lungs), lobes of the lungs, bronchi, bronchioles, and alveoli. This part is mainly responsible for gas exchange, especially at the alveolar level, where oxygen enters and carbon dioxide leaves the blood.

lower respi system

Passageway for air — it conducts air to and from the lungs but no gas exchange occurs here.

conducting zone

parts of the conducting zone

nose pharynx larynx trachea primary, secondary, tertiary bronchi bronchioles terminal bronchioles

Site of gas exchange — oxygen and carbon dioxide move between the air and the blood.

respiratory zone

parts of the respiratory zone

respiratory bronchioles alveolar ducts alveolar sacs alveoli

the overall process by which the body exchanges gases — oxygen (O₂) and carbon dioxide (CO₂) — between the air and the cells. It happens in two main stages

respiration

the exchange of gases between the alveoli (air sacs) in the lungs and the pulmonary capillary blood. Oxygen enters the blood, and carbon dioxide leaves it.

external respiration

the exchange of gases between the blood and the body’s tissues. Oxygen moves into the cells, while carbon dioxide moves from the cells into the blood.

internal respiration

refers to the mechanical movement of air in and out of the lungs — this is what we call breathing. It depends on the thoracic cage (ribs and muscles) and the diaphragm (main breathing muscle).

ventilation

The diaphragm contracts and moves downward, and the chest cavity expands. This expansion creates negative pressure inside the lungs, drawing air in.

active

The diaphragm relaxes and moves upward, and the chest cavity returns to its normal size. Air is pushed out of the lungs naturally as the pressure inside increases.

passive

refers to the exchange of air between the alveoli and the external environment, which determines how effectively gas exchange occurs. It is influenced by lung volumes and capacities

alveolar ventilation

Air always moves from areas of higher pressure to areas of lower pressure. During inhalation, pressure inside the lungs becomes lower (negative) compared to the atmosphere, so air flows into the lungs. During exhalation, pressure inside becomes higher, so air flows out.

air pressure variances

Refers to how easily air can flow through the airways. It depends on the diameter (radius) of the airways — narrower airways = more resistance.

airway resistance

The elasticity and expandability of the lungs and thoracic structures.

compliance

The pressure inside the lungs (intrapulmonary pressure) is normally slightly ___ compared to atmospheric pressure

negative

The amount of air inhaled or exhaled in one normal breath

tidal volume TV

normal tidal volume

500 ml

The extra air that can be inhaled after a normal inspiration

inspiratory reserve volume IRV

normal IRV

3000 ml

The extra air that can be exhaled after a normal expiration

Expiratory Reserve Volume (ERV)

normal ERV

1100 ml

The air that remains in the lungs after maximal exhalation

residual volume RV

normal RV

1200 ml

The maximum amount of air that can be exhaled after a full inhalation. It includes tidal volume + inspiratory reserve volume + expiratory reserve volume.

vital capacity VC

normal VC

4600 ml

The maximum amount of air that can be inhaled after a normal exhalation. It includes tidal volume + inspiratory reserve volume.

inspiratory capacity IC

normal IC

3500 ml

The amount of air left in the lungs after a normal exhalation.

functional residual capacity FRC

normal FRC

2300 ml

The total amount of air the lungs can hold after the deepest possible breath.

total lung capacity TLC

normal TLC

5800 ml

are tiny air sacs in the lungs where gas exchange (oxygen and carbon dioxide transfer) occurs.

alveoli

Make up the majority of the alveolar surface. Responsible for the actual gas exchange between air and blood.

type 1 alveoli

Produce surfactant, a fatty substance that reduces surface tension inside the alveoli. Surfactant prevents alveoli from collapsing during exhalation and helps them reopen easily during inhalation. It also interacts with pathogens and supports immune defense within the lungs.

type 2 alveoli

functions of surfactant

lowers surface tension prevents alveolar collapse interacts w pathogens modulates immune responses

The shorter the distance between the air and blood, and the greater the surface area, the faster and more efficient the diffusion of gases will be.

fick's law

Refers to the actual exchange of O₂ and CO₂ between the alveoli and the pulmonary capillaries. O₂ diffuses from the alveoli (high O₂) → blood (low O₂). CO₂ diffuses from the blood (high CO₂) → alveoli (low CO₂).

pulmonary diffusion

Refers to the blood flow through the pulmonary capillaries / vasculature — it brings deoxygenated blood to the alveoli for gas exchange and carries oxygenated blood back to the heart.

pulmonary perfusion

Measures efficiency of matching air to lungs (ventilation) and blood to lungs (perfusion)

ventilation perfusion ratios (V/Q)

normal V/Q ratio

4:5 or 0.8

V/Q > 0.8 → Ventilation exceeds perfusion (adequate air, poor blood flow). Gas exchange is impaired because air reaches alveoli that are not well perfused. Common causes: Pulmonary embolism, pulmonary infarction, emphysema.

dead space

V/Q < 0.8 → Perfusion exceeds ventilation (adequate blood flow, poor air entry). Blood passes through unventilated alveoli, leading to hypoxemia. Common causes: Pneumonia, atelectasis, mucus plug, asthma, tumor.

shunt

Absence or severe limitation of both ventilation and perfusion. Little to no gas exchange occurs. Commonly observed in: Pneumothorax, severe ARDS (Acute Respiratory Distress Syndrome).

silent unit

A nuclear medicine test used to detect V/Q mismatch and diagnose pulmonary embolism.

V/Q scan

Patient inhales a radioactive gas or aerosol; imaging shows air distribution in the lungs.

ventilation phase (part 1)

A radioactive substance is injected intravenously; imaging shows blood flow through the lungs.

perfusion phase (part 2)

INTRO TO OXYGENATION Flashcards

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