Transportation and Respiration - Part 2: The Heart and Lungs

The Anatomy of the Heart

The septum is a thick wall of muscle that separates the left and right ventricles.

How is blood pressure measured? 

Blood pressure is read as a relationship between two numbers: systolic (top) and diastolic (bottom) pressure. The units for blood pressure are mmHg, which stands for “millimeters mercury.”

Diastolic Pressure Definition

The amount of pressure the blood exerts on the walls of the arteries when the ventricles are relaxed.

Systolic Pressure Definition

The amount of pressure the blood exerts on the walls of the arteries when the ventricles contract.

What are some causes of high blood pressure?

Obesity / being overweight, genetic factors, not enough physical activity, age, and a diet high in salt.

What are some causes of low blood pressure?

Pregnancy, heart conditions, dehydration, blood loss, tobacco use, and too much alcohol.

Hypertension Definition

High blood pressure.

Hypotension Definition

Low blood pressure.

What is a stroke / what causes a stroke?

Strokes happen when __blood flow (oxygen supply) is cut off to an area of the brain__, causing it to become damaged or cause brain cell death in that area.

This can either happen if __a clot forms in a capillary in the brain__ or __moves to a capillary in the brain__ from another area of the body, or if a __capillary bursts in the brain__.

What stroke risk factors can you control?

Things that cause strokes but you can change are high blood pressure, smoking, high cholesterol, diabetes, birth control, alcohol, and weight. 

What stroke risk factors are out of your control?

Age, gender, ethnic origin, family history, and prior strokes / mini strokes.

What is moved around your body by the circulatory system? 

Oxygen, nutrients, and hormones to the cells. 

Carbon dioxide, nitrogenous wastes, and hormones away from the cells. 

How does the circulatory system maintain homeostasis? 

By carrying __nutrients to cells__, carrying __wastes away from cells__, carrying __hormones from cells in one part of the body to the target tissues__, __distributing heat__ throughout the body, __maintaining body fluid levels__, and __providing defense__ against invading organisms. 

What is bloodletting / phlebotomy?

Bloodletting is a process where __“bad blood” is removed from a person’s body to cure illnesses__ like fevers, coughs, headaches, inflammations, and hemorrhages.

Doctors thought that the drained blood could be replaced within a few hours by new, healthy blood.

Why is bloodletting bad?

It drops blood volume, which lowers blood pressure. The low blood pressure messes up transport systems and homeostasis because your body will not be able to transport things like nutrients, oxygen, etc. to the parts of the body that need it, which can cause death. 

The Anatomy of the Lungs

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Respiratory Pathways for Oxygen and Carbon Dioxide

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Why do we need to breathe? 

Your cells need oxygen to create energy. This energy is used to complete all sorts of vital functions in your body. 

How does oxygen get into body cells? 

The capillaries take oxygen from the alveoli in the lungs, and it is transported to the heart, then sent out to all parts of the body, where the capillaries pass it to the cells through diffusion. 

How is carbon dioxide removed from the lungs? 

The capillaries pick up carbon dioxide from cells throughout the body, which passes through the heart and into the lungs. Capillaries in the lungs pass carbon dioxide to the alveoli and you breathe it out. 

External Respiration Definition

__Breathing__: When oxygen is taken from the external environment and carbon dioxide is returned to the external environment. Includes the transfer of oxygen and carbon dioxide into/out of the bloodstream with the alveoli.  

External Respiration Word Equation

carbon dioxide ⟺ oxygen

External Respiration Chemical Equation

CO2 ⟺ O2

Internal Respiration Definition

__Gas Exchange__: The process of transferring oxygen from the blood to the cells of the body and carbon dioxide back into the blood. It occurs between the capillaries and cells of the body and involves diffusion. 

Internal Respiration Word Equation

carbon dioxide ⟺ oxygen

Internal Respiration Chemical Equation

CO2 ⟺ O2

Cellular Respiration Definition

__Aerobic Respiration__: The process in cells that uses glucose and oxygen to create energy that is used to complete functions in the body. Carbon dioxide is a waste product of this process. 

Cellular Respiration Word Equation

glucose + oxygen ⇒ carbon dioxide + water + ATP

Cellular Respiration Chemical Equation

C6H12O6 + O2 ⇒ CO2 + H2O + ATP

Diagram of External, Internal, and Cellular Respiration

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What is negative pressure? 

Negative pressure is when the diaphragm contracts, increasing the volume of the chest cavity. This increase of volume lowers the air pressure in the lungs to below atmospheric pressure, creating a vacuum (inhalation). 

What is inspiration? 

When your diaphragm contracts, and at the same time the intercostal muscles contract to move your ribs up and out. This pulls at your lungs, forcing them to expand, and creating a negative pressure inside of them, which sucks in air from the outside. 

What is expiration? 

When your diaphragm and intercostal muscles relax, your chest cavity shrinks, squishing the air out of your lungs and expelling it through your oral and nasal cavities. 

Diagram of Inspiration and Expiration

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What is your diaphragm? 

The diaphragm is a dome shaped muscle that contacts when you inhale.

Breathing Negative Feedback Loop

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Where in the cell does cellular respiration happen? 

The mitochondria. 

What is the normal range for blood pressure? 

Between 120/80mmHg and 140/90mmHg. 

What device measures blood pressure? 

A sphygmomanometer. 

Where in your body is your blood pressure the highest? 

In the __aorta__ (the left ventricle in the heart has a higher pressure, but blood pressure is defined as the pressure on the arteries, so it is not included). 

Why is it important to know your blood pressure? 

Because __high blood pressure__ greatly increases your risk of heart disease and stroke.

On the contrary, even __moderate forms of low blood pressure__ can cause dizziness, weakness, fainting, and an increased risk of injury.

__Severely low blood pressure__ can deprive your body of enough oxygen to carry out its normal functions, leading to damage to your heart and brain. 

Capillaries, Veins, and Arteries Flow Chart

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Aorta Definition

The largest artery in the body. 

Pleura Definition

A membrane that envelops each lobe of the lungs. 

Intercostal Muscles Definition

The muscles between the ribs that help with breathing. 

Blood Pressure Definition

The amount of pressure exerted on the walls of your arteries by your blood.

Homeostasis Definition

The maintenance of relatively stable internal conditions even though external conditions constantly change; __balance__. 

Negative Feedback Definition

Any change or deviation from the normal range of function is opposed or resisted. 

Positive Feedback Definition

A system that does not regulate itself and instead builds upon itself, increasing the current condition. 

Aerobic Definition

Uses oxygen. 

Anerobic Definition

Does not use oxygen. 

Respiration Definition

A process that takes place in all living cells of an organism where they produce energy by intake of oxygen and liberation of carbon dioxide. Therefore, __anything that has cells respires__.

Thorax Definition

The part of the body between the neck and the abdomen; the chest. 

Interpleural Fluid Function

Reduces the friction between the lungs and the thoracic wall during breathing.

What colour is deoxygenated and oxygenated blood?

__Deoxygenated blood is a dark red / deep rust colour__. It only looks blue in your veins because your skin has a yellow tint.

__Oxygenated blood is a brighter red colour.__

How thick are the membranes of the alveoli and capillaries?

__One cell__. This is to allow for gas exchange (diffusion).

What triggers you to take a breath?

When the chemoreceptors in your body sense that __your blood pH level is too low (acidic) because you have too much carbonic acid in your blood__ and you need to get rid of it.

What is your trachea made of and why?

Your trachea is made of __cartilage__. This is because __it needs to be flexible__ so it does not break and puncture your lungs or heart, __but also strong__ so you do not suffocate when you lay down or go underwater.