In your A-level biology you’ll be expected to compare and contrast mass transport systems. Here, we’ll take a look at the the mammalian cardiovascular system (circulatory system). 

a-level biology cardiovascular system summary revision notes and knowledge check PDF

When organisms develops organs and organ systems in order to maximise exchange (i.e. gas exchange systems), these organisms also need a mass transport system – a network of vessels circulating and connecting large volumes of fluid (ie. blood) and dissolved substances to organs and tissues around the body.

This transport system is also known as a mass flow system. For example, many plants have vascular systems composed of the xylem and phloem; Mammals (like Humans) and other animals have circulatory systems composed of the heart and blood vessels (arteries, capillaries and veins).

Mammals are endothermic animals with a high metabolic rate. Which means an efficient circulatory system is needed in order to deliver large amounts of raw materials (e.g. oxygen and glucose) to cells, tissues and organs. The system must also take away waste products (e.g. carbon dioxide). In order to do this efficiently, mammals have a double circulatory system i.e. a pulmonary system and a systemic circulatory system.

What is pulmonary circulation?

Pulmonary: - pulmonary = lungs

Circulation: - movement of fluids in a closed system.

 

Pulmonary circulation takes blood on a relatively short return journey to and from the the lungs.

 

When gas exchange takes place in the alveoli, pressure is lost. So, oxygenated blood must now be transported to the heart (our muscular pump) which pumps oxygenated blood around the body (systemic circulation).

What is Systemic circulation?

A-Level biology a sumary of the cardiocascular system - learnbiology.net

Systemic: - the ‘body’ / organism.

Circulation: -movement of fluids in a closed system.

 

In systemic circulation the heart pumps blood to the body. Blood is transported through a series of ever decreasing blood vessels (arteries - arterioles - capillaries). When blood passes through a system of capillary beds at tissues and exchange takes place pressure is lost once more. Following the exchange of materials (e.g. oxygen supplied to tissues and the waste product carbon dioxide picked up by the blood). Now, the deoxygenated blood must return to the heart, where the necessary ‘pressure boost’ pumps the deoxygenated blood to the lungs and the cycle continues.

Watch the lesson below which describes the mammalian circulatory system in terms you must understand for your a-level biology. Download the A3 Poster (PDF) and the interactive knowledge check work booklet (PDF) to help you before moving on to the structure and function of blood vessels (Arteries, Capillaries and Veins).

A Level Biology -

The Cardiovascular System (CVS) An Overview.

 

Check Where this Lesson fits into your Exam Specification!

a-level biology cardiovascular system summary revision notes and knowledge check PDF
a-level biology cardiovascular system summary revision notes A3 Poster PDF

A Level Biology - Cardiovascular System: 

Arteries and Arterioles.

 

Check Where this Lesson fits into your Exam Specification!

Arteries and Arterioles structure and function for a-level biology revision notes and knowledge check pdf
Arteries and Arterioles structure and function for a-level biology revision notes Poster A3 PDF

A Level Biology - Cardiovascular System: 

Capillaries.

 

Check Where this Lesson fits into your Exam Specification!

Capillaries structure and function for a-level biology revision notes and knowledge check pdf
Capillaries structure and function for a-level biology revision notes Poster A3 PDF

A Level Biology - Cardiovascular System: 

Veins.

 

Check Where this Lesson fits into your Exam Specification!

Veins structure and function for a-level biology revision notes and knowledge check pdf
Veins structure and function for a-level biology revision notes Poster A3 PDF

A Level Biology - Cardiovascular System: 

The Heart.