9. Transport in Animals (Part 1) (Cambridge IGCSE Biology 0610 for exams in 2023, 2024 and 2025)

Summary

This IGCSE study video explores the transport systems in animals, focusing on the circulatory system's role in nutrient and gas transport. It explains the single circulatory system of fish and the double circulation found in mammals, highlighting the heart's structure and function. The video also delves into the effects of physical activity on heart rate and discusses coronary heart disease, its causes, and prevention methods. Aimed at providing a clear understanding of these biological concepts, the video invites viewers to subscribe for more educational content.

Takeaways

• 🌊 Fish have a single circulatory system with a two-chambered heart consisting of an atrium and a ventricle, which allows blood to pass through the heart only once for a full circuit.
• 🐟 In fish, oxygenation occurs at the gills, and the circulatory system includes gill circulation and systemic circulation, with oxygenated blood moving to body capillaries after gill exchange.
• 💓 Mammals possess a double circulatory system with a four-chambered heart, enabling blood to pass through the heart twice for one complete body circuit.
• ❤️ The right side of the mammalian heart handles pulmonary circulation, pumping deoxygenated blood to the lungs for oxygenation.
• 💚 The left side is responsible for systemic circulation, delivering oxygenated blood from the lungs to the rest of the body.
• 🔄 Double circulation in mammals is advantageous for efficient oxygen and glucose delivery due to higher blood pressure compared to single circulation systems.
• 🦴 The heart's structure includes the right atrium, right ventricle, left atrium, and left ventricle, with valves ensuring one-way blood flow.
• 🔍 Coronary arteries are crucial for supplying oxygen-rich blood to the heart muscle itself, wrapping around the exterior of the heart.
• 💪 The ventricles have thicker muscular walls than the atria, with the left ventricle being the thickest to handle higher pressure requirements for systemic circulation.
• 🏃‍♂️ Physical activity increases heart rate as muscles require more oxygen and glucose for respiration, and waste products need to be removed more rapidly.
• 🚑 Coronary heart disease occurs when coronary arteries are blocked, leading to a heart attack due to oxygen starvation in heart muscles, often caused by cholesterol buildup.
• 🍏 Risk factors for coronary heart disease include diet, lack of exercise, diabetes, obesity, stress, smoking, genetic predisposition, age, and gender, with males being at higher risk.

Q & A

What is the main function of the circulatory system in animals?

The main function of the circulatory system in animals is to transport nutrients and gases, such as oxygen, throughout the body via the blood.

How does the single circulatory system in fish differ from the double circulatory system in mammals?

In fish, which have a single circulatory system, blood passes through the heart only once to complete a full circuit through the body, whereas in mammals, with a double circulatory system, blood passes through the heart twice for every one circuit of the body.

What are the two main types of blood flow in the circulatory system of fish?

The two main types of blood flow in fish are oxygenated blood flow (pink arrows), which is rich in oxygen, and deoxygenated blood flow (blue arrows).

How does a fish's heart structure support its single circulatory system?

A fish's heart supports its single circulatory system with two chambers: an Atrium and a Ventricle, which allow blood to pass through the heart only once for a complete circuit.

What is the advantage of a double circulatory system in mammals over a single circulatory system in fish?

A double circulatory system in mammals allows for faster and more efficient delivery of oxygen and glucose throughout the body due to higher blood pressure, which is essential for larger organisms with greater oxygen demands.

How many chambers does the heart of a mammal have, and what is the significance of this?

A mammalian heart has four chambers, which allows for the separation of pulmonary and systemic circulation, enhancing the efficiency of oxygen and nutrient delivery to the body.

What are the functions of the valves in the heart?

The valves in the heart, such as the tricuspid and bicuspid valves, ensure one-way flow of blood by preventing it from flowing back into the atria. Semilunar valves prevent blood from flowing back into the heart from the arteries.

What is the role of the coronary arteries in the heart?

The coronary arteries supply oxygen-rich blood to the heart muscle itself, ensuring that the heart can function and pump blood efficiently.

Why do the ventricles have thicker muscle walls than the atria?

The ventricles have thicker muscle walls than the atria because they are responsible for pumping blood out of the heart at higher pressures, whereas the atria only need to move blood into the ventricles.

How does physical activity affect the heart rate, and why?

Physical activity increases the heart rate because the body's muscle cells require more energy, oxygen, and glucose for respiration, and the waste products need to be removed more quickly. The heart rate increases to meet these demands.

What is coronary heart disease, and what are its main causes?

Coronary heart disease occurs when the coronary arteries become blocked, leading to a lack of blood and oxygen supply to the heart muscles, which can result in a heart attack. It is mainly caused by the buildup of cholesterol and fatty substances within the coronary arteries.

Outlines

00:00

🐟 Single and Double Circulatory Systems

This paragraph introduces the concepts of single and double circulatory systems, focusing on the transport of nutrients and gases in animals. It explains that the circulatory system is a network of blood vessels with a pump and valves ensuring one-way blood flow. Fish have a single circulatory system with two-chambered hearts, where blood is oxygenated at the gills and completes a circuit through the body. The paragraph also contrasts this with the double circulatory system of mammals, which has four-chambered hearts and two distinct circulations: pulmonary (deoxygenated blood to the lungs) and systemic (oxygenated blood to the body). Diagrams are used to illustrate these processes.

05:04

💓 Detailed Anatomy of the Mammalian Heart

This section delves into the anatomy of the mammalian heart, highlighting its four chambers: the right and left atria and ventricles. It describes the flow of deoxygenated blood from the body to the lungs via the right side of the heart and the oxygenated blood from the lungs to the body via the left side. The paragraph explains the function of various valves, such as the tricuspid and bicuspid valves, and the semilunar valves in the pulmonary artery and aorta. It also touches on the importance of the septum in preventing the mixing of oxygenated and deoxygenated blood. A simplified diagram aids in visualizing the double circulation process.

10:06

🚀 Impact of Physical Activity on Heart Rate

This paragraph explores the relationship between physical activity and heart rate, detailing an experiment to measure pulse rate at rest and during exercise. It explains that during exercise, the body's muscle cells require more energy, oxygen, and glucose for respiration, leading to an increased heart rate to meet these demands. The paragraph also discusses the concept of oxygen debt and how the heart rate increases to repay it. Additionally, it covers the monitoring of heart activity through ECG, pulse rate, and stethoscope sounds, emphasizing the need for a healthy lifestyle to maintain heart health.

15:08

💔 Coronary Heart Disease and Its Risk Factors

The final paragraph discusses coronary heart disease, a condition where the coronary arteries become blocked, leading to a lack of oxygen in the heart muscles and potentially causing a heart attack. It explains the causes of this disease, which include the buildup of cholesterol and fatty substances in the arteries. The paragraph outlines the risk factors for coronary heart disease, such as diet, lack of exercise, diabetes, obesity, stress, smoking, genetic predisposition, age, and gender. It concludes with ways to reduce the risk of coronary heart disease, including quitting smoking, maintaining a healthy diet, and regular exercise.

Keywords

💡Circulatory System

The circulatory system is a biological network responsible for the transport of nutrients, gases, and waste products throughout an organism. In the context of the video, it is the primary focus, explaining how it operates in both fish and mammals. The script describes the single circulatory system in fish and the double circulatory system in mammals, highlighting the differences in structure and function.

💡Single Circulatory System

This term refers to a type of circulatory system found in fish, where blood passes through the heart only once to complete a circuit through the body. The video script explains that in this system, deoxygenated blood is pumped to the gills where it absorbs oxygen, becoming oxygenated, and then circulates to the rest of the body.

💡Double Circulatory System

This term describes the circulatory system found in mammals, which involves blood passing through the heart twice for every circuit of the body. The script outlines the process, detailing the paths of oxygenated and deoxygenated blood, and the role of various heart chambers and vessels in this system.

💡Heart Chambers

Heart chambers refer to the sections within the heart that facilitate the flow of blood. The script specifies that fish hearts have two chambers—an atrium and a ventricle—while mammalian hearts have four, allowing for the double circulation process. These chambers are crucial for the separation and direction of blood flow.

💡Oxygenated and Deoxygenated Blood

Oxygenated blood is rich in oxygen and is transported to the body's tissues, while deoxygenated blood has released its oxygen and is in need of reoxygenation. The video script uses these terms to describe the flow of blood in both single and double circulatory systems, emphasizing the importance of oxygen in the blood's function.

💡Gill Circulation

Gill circulation is the process by which blood is pumped to the gills in fish to be oxygenated. The script explains that in a single circulatory system, this is a key step where deoxygenated blood from the body is transformed into oxygenated blood through the gills.

💡Systemic Circulation

Systemic circulation refers to the flow of blood through the body's systemic arteries to supply oxygen and nutrients to the tissues and organs. The script describes this process in both fish and mammals, where oxygenated blood is distributed to the body after being processed in the gills or lungs, respectively.

💡Pulmonary Circulation

Pulmonary circulation is the route by which deoxygenated blood is transported from the heart to the lungs to be oxygenated. The script explains this process in the context of the double circulatory system in mammals, detailing the path from the right side of the heart to the lungs and back.

💡Coronary Arteries

Coronary arteries are the blood vessels that supply oxygen-rich blood to the heart muscle itself. The video script discusses their importance in maintaining the health of the heart and the potential issues that can arise when they become blocked, leading to coronary heart disease.

💡ECG

ECG, or electrocardiogram, is a diagnostic tool used to measure and record the electrical activity of the heart. The script mentions ECG as a method to monitor heart activity, which can be indicative of the heart's health and function.

💡Coronary Heart Disease

Coronary heart disease is a condition where the coronary arteries become blocked, leading to a lack of oxygen supply to the heart muscle and potentially causing a heart attack. The script describes the causes, risk factors, and prevention strategies for this disease, emphasizing its relevance to the overall theme of cardiovascular health.

Highlights

Introduction to IGCSE study buddy for biology revision.

Explanation of the circulatory system's role in transporting nutrients and gases in animals.

Description of the single circulatory system in fish with two-chambered hearts.

Illustration of oxygenated and deoxygenated blood flow in fish.

Clarification on fish respiration through gills instead of lungs.

Overview of the double circulatory system in mammals with four-chambered hearts.

Diagrammatic representation of mammalian double circulation.

Differentiation between pulmonary and systemic circulation in mammals.

Advantage of double circulation for efficient oxygen and glucose delivery in mammals.

Structural details of the mammalian heart, including atria and ventricles.

Function of valves in preventing backflow of blood in the heart.

Role of the septum in separating oxygenated and deoxygenated blood.

Importance of the aorta in distributing oxygenated blood throughout the body.

Simplified diagram for understanding the double circulation process.

Memory aid for differentiating arteries and veins based on blood flow direction.

Discussion on coronary arteries supplying oxygen-rich blood to the heart muscle.

Comparison of muscular walls' thickness between atria and ventricles.

Explanation of how physical activity affects heart rate and its recovery.

Investigation of the impact of exercise on heart rate through an experiment.

Understanding coronary heart disease and its causes.

Risk factors and prevention methods for coronary heart disease.

Conclusion of chapter 9 part 1 on transport in animals.

Transcripts

hi everyone welcome to IGCSE study buddy

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the Cambridge IGCSE syllabus

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this video summarizes part 1 of chapter

9 transport in animals

in most animals the circulatory system

is the primary method used to transport

nutrients and gases through the body in

the blood

the circulatory system is a system of

blood vessels with a pump and valves to

ensure one-way flow of blood

fish have a single circulatory system

the heart of a fish has two Chambers an

Atrium and a ventricle

in a single circulatory system blood

passes through the heart only once to

complete a full circuit through the body

of the fish

this diagram illustrates the single

circulation of a fish

the pink arrows represent the oxygenated

blood flow or blood rich in oxygen

the blue arrows represent deoxygenated

blood flow as you may notice fish do not

have lungs since oxygen is absorbed when

the blood passes the gills

so deoxygenated blood from the body

capillaries move through the two

chambers of a fisher's Heart The Atrium

and The ventricle and then reaches the

Gill capillaries where oxygen is

absorbed into the blood

thereafter the blood becomes oxygenated

and moves from the Gill capillaries to

the body capillaries completing one

circuit

so when the heart pumps the blood to the

gills to be oxygenated it's called Gill

circulation

the blood then continues through the

rest of the body before arriving back at

the atrium and this is called systemic

circulation

moving on to the double circulation of a

mammal

so mammals have a double circulatory

system

the mammalian heart has four chambers

this means that blood passes through the

heart twice for every one circuit of the

body

so here's a diagram to explain the

double circulation of a mammal

the Red Arrows represent the oxygenated

blood flow and the blue arrows represent

deoxygenated blood flow

the heart is labeled as if it was in the

chest so what is on your left on a

diagram is actually the right hand side

and vice versa

so deoxygenated blood enters the right

atrium labeled as r a on the diagram via

the vena cava

then it moves into the right ventricle

next the deoxygenated blood is pumped by

the right ventricle to the lungs to

become oxygenated

the pulmonary artery carries this blood

away from the heart

gas exchange happens at the lungs and

the deoxygenated blood becomes

oxygenated blood

then oxygenated blood enters the left

atrium via the pulmonary vein

then it moves to the left ventricle

oxygenated blood is pumped by the left

ventricle to the wrist of the body

the aorta carries this oxygenated blood

away from the heart

body cells use the oxygen and cause the

blood to become deoxygenated

the deoxygenated blood returns to the

heart and the cycle repeats

the right side of the heart receives

deoxygenated blood from the body and

pumps it to the lungs that is called

pulmonary circulation

the left side of the heart receives

oxygenated blood from the lungs and

pumps it to the body this is called

systemic circulation

what is the advantage of a double

circulation

mammals are larger than fish so they

have a greater requirement for oxygen

and glucose for respiration

double circulation allows this oxygen

and glucose to be delivered faster and

more efficiently through the blood since

a double circulation maintains a higher

blood pressure than a single circulation

system

let's learn the structures of the

mammalian heart now

this is the right atrium one of the

heart's four chambers

this is the vena cava deoxygenated blood

coming from the body flows into the

right atrium through this vein

this is the tricuspid valve it is an

atrioventricular valve which separates

the Atria from the ventricles on each

side of the heart and prevents the blood

from flowing back into the Atria

once the right atrium is filled with

blood the heart muscles of the right

atrium contracts and the blood is pushed

through the tricuspid valve into the

right ventricle

this is the right ventricle the next

chamber of the heart

this is the semilunar valve it prevents

blood flowing backwards into the heart

the walls of The ventricle contract and

the blood is pushed through the

semilunar valve into the pulmonary

artery

this is the pulmonary artery it is a

blood vessel that carries deoxygenated

blood away from the heart to the lungs

to be oxygenated

this is the septum it is a muscle wall

that separates the two sides of the

heart therefore it prevents the mixing

of oxygenated and deoxygenated blood

this is the left atrium another one of

the heart's four chambers

this is the pulmonary vein oxygenated or

oxygen rich blood returning from the

lungs enters the left atrium through

this vein

this is the bicuspid valve it is an

atrioventricular valve which separates

the left atrium from the left ventricle

and prevents the blood from flowing back

into the lift atrium

once the left atrium is filled with

blood the heart muscles of the left

atrium contracts and the blood is pushed

through the bicuspid valve into the left

ventricle

this is the left ventricle a chamber of

the heart

this is the semilunar valve in the aorta

it prevents blood flowing backwards into

the heart

the thicker muscle walls of The

ventricle contracts strongly to push the

blood forcefully through the semilunar

valve into the aorta

this is the aorta it is a blood vessel

that carries oxygenated blood away from

the heart all the way around the body

here's a simpler diagram that will guide

you through double circulation

deoxygenated blood enters the right

atrium through the vena cava

then it moves into the right ventricle

through the atrioventricular valve the

special name for the one on this side is

called the tricuspid valve

the right ventricle pumps the

deoxygenated blood out to the pulmonary

artery via the semilunar valve

the blood travels to the lungs and moves

through the capillaries past the alveoli

where gas exchange takes place

the deoxygenated blood becomes

oxygenated blood and returns to the

heart via the pulmonary vein into the

left atrium

it then moves into the left ventricle

through the atrioventricular valve the

special name for the one on this side is

called the bicuspid valve

the left ventricle pumps oxygenated

blood out to the aorta via the semilunar

valve

the aorta takes the oxygenated blood

away from the heart to the wrist of the

body

here's a small tip to remember which

vessels take blood away from the heart

remember a

pulmonary artery and aorta are arteries

and they carry blood away from the heart

so artery begins with a and so does away

blood this pump towards the heart in

veins and away from the heart in

arteries

next what are coronary arteries

the heart is made of muscle tissues

like all other tissues in the body the

heart muscle needs oxygen rich blood to

function

coronary arteries Supply blood to the

heart muscle

the coronary arteries wrap around the

outside of the heart

moving on to muscular walls the

ventricles have thicker muscle walls

than the Atria since they pump blood out

of the heart so they need to do so at a

higher pressure

so you will notice that the lower two

Chambers the ventricles have thicker

muscle walls than the upper two Chambers

the Atria

also comparing both ventricles the left

ventricles muscle wall is thicker than

the right ventricles muscle wall

this is because it has to pump blood at

a higher pressure to the whole body

whereas the right ventricle has to pump

blood just to the lungs

the activity of the heart may be

monitored by

using an ECG

measuring pulse rate

or listening to the sounds of valves

closing using a stethoscope

let's investigate the effect of physical

activity on the heart rate

first record the pulse rate at rest for

a minute

next exercise for a while

then record the pulse rate every minute

until it returns to the resting rate

this experiment will show that during

exercise the heart rate increases and

may take several minutes to return to

normal

so why does the physical activity have

this effect on the heart rate this is

because during exercise the muscle cells

of the body need more energy

therefore they need more oxygen and

glucose for respiration

the waste products of respiration also

needs to be removed faster from the

cells

moreover some of the muscle cells may

have respired anaerobically without

oxygen so the oxygen debt needs to be

repaid

the heart rate therefore increases to

meet these demands

finally let's learn about coronary heart

disease

so far we know that the heart functions

as a pump which delivers blood to the

rest of the body

however the heart muscles themselves

also need a blood supply because they

too are respiring muscles

coronary arteries Supply blood to the

heart muscles in order for them to

respire and perform their function

coronary heart disease is when the

coronary artery becomes blocked leading

to blood and therefore oxygen starvation

in the heart muscles

this leads to a heart attack

coronary heart disease is caused by the

buildup of cholesterol and other fatty

substances within the coronary arteries

so in this diagram you can see a

coronary artery with normal blood flow

and a coronary artery with a cholesterol

buildup which is restricting the blood

flow

the possible risk factors for coronary

heart disease include

diet eating unhealthy amounts of

saturated fats increases cholesterol

levels in the body lack of exercise

physical activity can help control blood

cholesterol diabetes and obesity so an

inactive person is at a higher risk of

getting this disease

stress increases the blood pressure

increasing the chance of coronary

arteries getting blocked

smoking increases blood pressure and

increases the likelihood of clots

forming in the arteries

genetic predisposition children of

parents with coronary heart disease are

more likely to develop coronary heart

disease

age with increasing age the risk of

getting coronary heart disease increases

and gender males have a higher chance of

developing coronary heart disease than

females

the risk of coronary heart disease may

be reduced in the following ways

quit smoking

maintain a healthy diet with reduced

animal fats

and exercise regularly

so that concludes part 1 of chapter 9

transport in animals

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