Skip to content Skip to navigation

Connexions

You are here: Home » Content » 2.3.1 Blood circulatory system

Navigation

Lenses

What is a lens?

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

This content is ...

Affiliated with (What does "Affiliated with" mean?)

This content is either by members of the organizations listed or about topics related to the organizations listed. Click each link to see a list of all content affiliated with the organization.
  • Life Science display tagshide tags

    This module is included inLens: Siyavula: Life Sciences (Gr 10 - 12)
    By: SiyavulaAs a part of collection: "Siyavula: Life Sciences Grade 10"

    Collection Review Status: In Review

    Click the "Life Science" link to see all content affiliated with them.

    Click the tag icon tag icon to display tags associated with this content.

Recently Viewed

This feature requires Javascript to be enabled.

Tags

(What is a tag?)

These tags come from the endorsement, affiliation, and other lenses that include this content.
 

2.3.1 Blood circulatory system

Module by: Daniel Williamson. E-mail the author

Overview

All living cells require nutrients and oxygen to survive. Cells produce metabolic waste, which must be removed and excreted. The circulatory system is responsible from providing nutrients and removing metabolic waste.

Unicellular organisms have a simple system to allow for this and it is by diffusion where substances move from a high concentration to a low concentration.

Most invertebrates like a grasshopper have an open circulatory system , where blood (haemolymph) bathes the body organs.

By comparison, mammals have a closed circulatory system since blood is contained within blood vessels.

Pulmonary and Systemic circulatory systems

Open circulatory system

blood is pumped into a heamocoel (an open space or cavity) that surrounds to organs. Muscle movement also helps to pump then blood. Blood diffuses back the heart. Blood movement is sluggish. There is no difference between the blood and the interstitial fluid. Interstitial fluid is the fluid that surrounds the cells. Blood is not contained within capillaries.

Closed circulatory system

blood is pumped from the heart through arteries and returns to the heart via veins. Blood never leaves the vascular system (arteries, veins and capillaries). Nutrients, water and metabolic waste diffuses out of the vascular system and into the interstitial fluid. Interstitial fluid and blood are separated, by the vascular system. Interstitial fluid returns to circulation through the lymphatic system.

The Human Circulatory System

All mammals have a closed blood circulatory system - blood always flows inside blood vessels.

A double circulatory system = blood passes through the heart twice:

  1. Pulmonary circulation: the blood is pumped from the heart to the lungs to oxygenate the blood and then back to the heart.
  2. Systemic circulation (to all the systems): the blood is pumped from the heart to all parts of the body and back to the heart again.
  3. Coronary circulation : is a circulatory system that supplies the heart muscle with the blood it required in order to function.

Very simple simulation of blood flow through the systemic and pulmonary circulatory systems. The illustration shows each of these circulatory systems to be separate loops leaving from one side of the heart and returning to the other.

http :// www . biologyinmotion . com / cardio / index . html

Figure: Simplified Diagrammatic sketch of the entire circulatory system. Blood flows to every inch of the body, even to the tips of the fingers and toes. Lungs provide oxygen to the blood. The digestive system supplies nutrients. The kidneys filter the blood.

The Heart and Associated Blood Vessels

Figure 1
Figure 1 (graphics1.png)

Figure 1 : Heart overlayed on a body so show the location of the heart within the chest. http://en.wikipedia.org/wiki/File:Surface_anatomy_of_the_heart.png

  • The heart is situated in your thorax just behind your breastbone and is about the size of your fist.
  • It is a large muscle that pumps through repeated rhythmic contractions and therefore requires lots of nutrients and oxygen.
  • On the surface of the heart are coronary arteries that are arteries that branch off the aorta and supply the heart with oxygen and nutrients.
  • The heart is made up of 4 chambers and divided by a septum into a right and left half.
  • The right half of the heart pumps deoxygenated blood up into the pulmonary artery, towards the lungs (pulmonary circulation), where it is oxygenated.
  • Oxygenated blood returns from the lungs via the pulmonary veins and enters the left side of the heart.
  • The left side of the heart then pumps oxygenated blood up through the aorta, and into the general circulation (systemic circulation) and the oxygen is consumed by the body.
  • Deoxygenated blood returns to the right side of the heart via the inferior vena cava which drains blood from below the heart and superior vena cava, which brings blood from the head and arms.
  • The human circulatory system is a double circulatory system, because blood travels to the heart twice during circulation, once before going to the lungs and once before circulating throughout the body.
  • Blood only flows in one direction, through the circulatory system.
  • All vessels that flow A way from the heart are called A rteries.
  • All blood vessels entering the heart are called V eins.
  • The terms artery and vein are not determined by what the vessel transports (oxygenated blood or deoxygenated) but by whether the vessel flows to or from the heart.
Figure 2
Figure 2 (graphics2.png)

Figure 2 : General structure of the heart and associated blood vessels (http://en.wikipedia.org/wiki/File:Anatomy_Heart_English_Tiesworks.jpg)

internal structure of the heart

  • The heart is made up of 4 chambers. There are 2 atria at the top of the heart which receives blood and 2 ventricles at the bottom of the heart which pumps blood out of the heart.
  • The septum divides the left and right side of the heart.
  • The valves of the heart ensure that blood only flows one way through the heart.

The tricuspid valve is found between the right atrium and the right ventricle.

The mitral valve is found between the left atrium and the left ventricle.

Strong tendinous chords attached to valves prevent them from turning inside out when they close.

The semi-lunar valves are located at the bottom of the aorta and pulmonary artery.

Figure 3: Internal structure of the heart
Figure 3 (graphics3.png)

Interesting facts : Humans, birds, and mammals have a four-chambered heart. Fish have a two- chambered heart, one atrium and one ventricle. Amphibians have a three- chambered heart with two atria and one ventricle. The advantage of a four chambered heart is that there is no mixture of the oxygenated and deoxygenated blood.

Table 1
Figure 4
Figure 4 (graphics4.png)
Figure 5
Figure 5 (graphics5.png)
Figure 6
Figure 6 (graphics6.png)
Figure 7
Figure 7 (graphics7.png)
Figure 4. The relationship of the heart and circulatory system to major visceral organs.
 
 

The circulatory song http://www.youtube.com/watch?v=q0s-1MC1hcE&NR=1

The Cardiac Cycle

  • The human heart will undergo over 3 billion contraction cycles, as shown in Figure 5, during a normal lifetime.
  • The heart beats in a rhythmic cycle. A complete cardiac cycle is one round of the heart pumping blood.
  • The top half of the heart works as one unit.
  • The bottom half of the heart works as one unit.
  • The sino-atrial node (pacemaker) starts and regulates the process.
  • The cardiac cycle consists of two parts: systole (contraction of the heart muscle) and diastole (relaxation of the heart muscle).

Atrial systole (0.1s)

  • Atria contract simultaneously, pushing blood into the ventricles
  • Ventricles are relaxed
  • Atrio ventricular valves open
  • Semi lunar valves close

Ventricular systole (0.3s)

  • Atria relax
  • Ventricles contract simultaneously
  • Blood enters aorta and pulmonary artery
  • Semi lunar valves open
  • Atrio ventricular valves close

Diastole (0.4s)

  • Atria and ventricles relax
  • Atrio ventricular valves open
  • Blood enters atria and ventricles
  • Semi lunar valves close
  • Back flow in arteries prevented

The heart beat can be heard as a sound that the valves make when they close. The ‘lub’ sound is made when the atrio ventricular valves close and the ‘dub’ sound is made when the semi lunar valves close.

Figure 8
Figure 8 (graphics8.jpg)

Figure 5

from mindset – (please check permission from this, found it in Biology 6th edition Campbell and Reece)

Cardiac Cycle: flow of blood through the heart

Excellent simple video illustrating the heart cycle.

http://www.youtube.com/watch?v=D3ZDJgFDdk0

Blood Pressure

  • The blood pressure is produced by the left ventricle contractions.
  • The rhythm of ventricle diastole, often just referred to as diastole, causes the pulse, which can be felt by holding two finders to the side of the throat.
  • Blood pressure oscillates with the contraction of the left ventricle.

Ideal blood pressure for an adult is:

Systolic pressure: 120 mm HG

Diastolic blood pressure: 80 mm HG

A usual rule is that systolic pressure should be 100 plus your age but never more than 140 and diastolic pressure should not be over 90.

Table 2
 
Figure 9
Figure 9 (graphics9.png)

Figure 6 The cardiac cycle. Image from Purves et al., Life: The Science of Biology , 4th Edition, by Sinauer Associates ( www.sinauer.com ) and WH Freeman ( www.whfreeman.com ),(please get permission)

Normal Heart Sounds

http://upload.wikimedia.org/wikipedia/commons/7/72/HROgg.ogg

Lung and pulmonary system

Khan Academy video on the pulmonary system. Overview on breathing.

http://www.khanacademy.org/video/the-lungs-and-pulmonary-system?playlist=Biology

  • The lungs serve as the air-blood interface.
  • Blood from the lungs is pumped into the pulmonary arteries.
  • From the pulmonary arteries the vascular system branches into smaller and smaller vessels until the blood is flowing through thin pulmonary capillaries.
  • These capillaries surround the alveoli in the lungs.
  • At this point there are only two layers of cells separating the blood from the air.
  • Carbon dioxide in deoxygenated blood diffused out of the blood.
  • Oxygen in the lungs diffuse in to the blood oxygenating it Oxygen is absorbed.
  • Oxygenated blood then returns to the heart vial the pulmonary veins.

Figure : Details arteries and veins connecting the heart to the lungs Red blood has been oxygenated, blue blood is deoxygenated. . (Wikipedia - http://en.wikipedia.org/wiki/File:Illu_pulmonary_circuit.jpg)

Figure 10
Figure 10 (graphics10.png)

Figure 11
Figure 11 (graphics11.png)

Figure : Very detailed image of the lungs, it is not necessary or required to know all this detail but this is a fantastic image of the lungs – wikipedia (http://en.wikipedia.org/wiki/File:Respiratory_system_complete_en.svg).

Major organs and systemic system: associated major blood vessels the brain, small intestines, liver, kidney. graphics12.png

Figure : Detailed illustration of the systemic circulation. http://en.wikipedia.org/wiki/File:Circulatory_System_en.svg

  • All the organs of the body are supplied by blood.
  • Each has an artery supplying the organ with blood from the heart, and veins returning blood to the heart.
  • Arteries and veins have been named according to the organ which they supply blood to.

The circulatory system forms a closed system.

  • Nutrients enter the circulatory system from the digestive system.
  • These nutrients first move to the liver via the hepatic portal vein, the liver then controls the nutrient composition of the blood.
  • Blood passes from the liver to the heart through the hepatic vein.
  • Nutrients are then circulated throughout the body.
  • Cells consume the nutrients in the blood and produce metabolic waste. T
  • his metabolic waste is circulated in the blood, if it remains in the blood the blood would eventually become toxic.
  • The kidneys are supplied with blood via the renal arteries and they remove metabolic waste from the blood, passing it to urine.
  • The Brain is supplied with blood via the carotid arteries and the vertebral arteries. The blood is drained via the jugular veins. The brain is supplied with 15% of the total amount of blood pumped by the heart.

Mechanisms for controlling cardiac cycle and heart rate (pulse)

  • The cardiac cycle is controlled by nerve fibers extending from nodes of nerve bundles through the heart muscle.
  • An electrical signal is triggered in the node.
  • The electrical signal then spreads through the fibers and causes the heart muscle to contract.

There are two nodes:

  1. The sinoatrial node (SA), which initiates the heart cycle. Electrical signals spread from the SA across the atria causing it to contact.
  2. The electrical signal also reaches the Atrioventricular node (AV) . Here the signal pauses, before spreading through the ventricles causing them to contract.
  • The SA is able to initiate the electrical signal without any stimulation for the nervous system, but it can be controlled by the nervous system.
  • The brain does not need to tell the heart to beat; it is able to beat on its own.
  • The brain can make the heart rate increase, when for instance you are scared or are running.
  • Hormones are also able to increase the heart rate.

Simple simulation of how electrical activity spreads over the heart.

Link : http://en.wikipedia.org/wiki/File:ECG_Principle_fast.gif

Measuring pulse rate: http://www.nlm.nih.gov/medlineplus/ency/article/003399.htm

How the Nodes cause contraction

  • Human heartbeats originate from the sinoatrial node (SA node) near the right atrium.
  • Modified muscle cells contract, sending a signal to other muscle cells in the heart to contract.
  • The signal spreads to the atrioventricular node (AV node).
  • Signals carried from the AV node, slightly delayed, through bundle of His fibers and Purkinjie fibers cause the ventricles to contract simultaneously. Figure 13 illustrates several aspects of this.
Table 3
Figure 13. The contraction of the heart and the action of the nerve nodes located on the heart. Images from Purves et al., Life: The Science of Biology , 4th Edition, by Sinauer Associates ( www.sinauer.com ) and WH Freeman ( www.whfreeman.com ), (please get permission)
Figure 12
Figure 12 (graphics13.png)
Figure 13
Figure 13 (graphics14.png)
Figure 14
Figure 14 (graphics15.png)

Electrical activity

  • The electrical activity in the heart is so strong that is can be measured from the surface of the body as an electrocardiaogram (ECG).
  • A normal heart has a very regular rhythm.
  • An abnormal heart may have an arrhythmia, or abnormal rhythm as shown in the figures.
Table 4
Figure 15. Normal cardiac pattern (top) and some abnormal patterns (bottom). Images from Purves et al., Life: The Science of Biology , 4th Edition, by Sinauer Associates ( www.sinauer.com ) and WH Freeman ( www.whfreeman.com ), (please contact for permission).
Figure 15
Figure 15 (graphics16.png)
Figure 16
Figure 16 (graphics17.png)

Investigation: Heart Health and Measuring Heart rate

Part 1: Investigating your cardiovascular fitness

Aim :To investigate your heart rate before, during and after strenuous aerobic exercise.

Method :

  1. Work in pairs on the field and ensure you have a stop watch.
  2. One partner performs the experiment and the other records the results. Partners then swap roles.
  3. Take the resting pulse rate before exercising.
  4. One partner runs quickly around the field twice.
  5. Immediately after the run take his pulse.
  6. Continue to take his pulse every minute for 5 minutes.
  7. Record the results and plot a graph using the data pertaining to you.

Results : Record results in a table like the one indicated below

Table 5
TIME HEART RATE (BEATS PER MINUTE)
Before exercise (resting)  
0 min (immediately after exercise)  
1 min (after exercise)  
2 min  
3 min  
4 min  
5 min  

Draw a line graph to illustrate your results on the following axis (show the resting pulse rate as a separate dotted line on the axis).

Mark allocation: heading x-axis scale x-axis label 

y-axis scale y-axis label plotting graph 

neat and done in pencil 

Questions:

1.Write a hypothesis for this investigation.

2.Write down the independent variable.

3.Write down the dependent variable.

4.Name ONE factor that must be kept constant during this investigation.

5.Write down TWO ways in which the accuracy of this investigation can be

improved.

6.What conclusions can be made about your cardiovascular fitness?

7.Explain why the heart rate increases during exercise?

Part 2: Investigating your family’s heart health:

Instructions:

  1. Draw up a table to record the answers to the following yes/no questions:

i. Do you smoke?

ii. Are you overweight?

iii. Do you exercise regularly?

iv. Do you follow a healthy diet (low fat, low salt)

v. Do you have your blood pressure checked regularly?

vi. Do you have a family history of heart and circulatory disease?

  1. Survey two adult male family member (father, grandfather or uncle) and two adult female family members (mother, grandmother or aunt). Include the adults’ first name, gender, age and relationship to you.

3.Record the results in your table. Also indicated the score they obtained:

i. yes=0; no=5

ii. yes=0; no=5

iii. yes=5; no=0

iv. yes=5; no=0

v. yes=5; no=0

vii. yes=0; no=5

4.Analyse the results by comparing the total score with the following descriptors:

30 marks- you take very good care of your heart. Well done!

25 marks- you take good care of your heart. Keep it up!

20 marks- you take reasonably good care of your heart but need to work

on a few aspects where you scored 0.

15 marks- you need to take better care of your heart.

0-10 marks- you do not look after your heart at all. It’s time to make a

change to a healthier lifestyle.

Assessment Rubric

Table 6
  • Results
0- not done1- poorly presented. 2- average presentation of results, but missing some detail.3- average presentation of results, including all salient features and information.4- good presentation of results, but missing some detail.5- good presentation of results, including all salient features and information. 		  5

Rich media:

Khan Academy

http :// www . khanacademy . org / video / circulatory - system - and - the - heart ? playlist = Biology

Cardiac Magnetic Resonance imaging of Beating heart: Large magnets are used to create images of the heart inside the body, without the need for surgery.

http://upload.wikimedia.org/wikipedia/commons/7/73/Four_chamber_cardiovascular_m agnetic_resonance_imaging.gif

View from the top

http://commons.wikimedia.org/wiki/File:Beating_Heart_axial.gif

View from the side

http://commons.wikimedia.org/wiki/File:Cardiac_mri_ani_sagittal_bionerd.gif

Blood Vessels

Structure and functioning of arteries, veins, capillaries and valves

Arteries

  • Arteries carry blood from away from the heart. The pressure created by the pumping heart forces blood down the arteries.
  • Arteries have three layers.
  1. Outside layer – connective tissue
  2. Middle layer – smooth muscle, allows contraction of the arteries to regulate blood flow and pressure
  3. Inside layer – single layer of tightly connected simple squamous endothelial cells
  • The large arteries close to the heart branch into smaller arterioles (smaller arteries) and eventually branch into capillaries.
Capillaries
  • Capillaries are little more than a single layer or endothelial cells.
  • Capillaries form intricate networks throughout the tissues.
  • They allow water, nutrients and gasses to diffuse out of the blood and waste materials to diffuse into the blood.
  • This exchange occurs between the blood and the interstitial fluid.
  • The interstitial fluid is the fluid surrounding the cells.
  • The blood never comes into contact with the cells.
  • The blood and interstitial fluid exchange material, and the interstitial fluid then exchanges material with the cells.
Veins
  • The intricate networks formed by the capillaries eventually converge to form venules, (small veins)
  • The venules then converge to form veins which return the blood to the heart.
  • Veins only consist of two layers.
  1. The outer layer is made up of connective tissue
  2. The inner layer is made up of endothelial cells.
Valves
  • Once the blood has passed through the capillaries very little blood pressure remains to return blood to the heart.
  • Instead of pressure from the heart veins use a series of valves to force blood to return to the heart.
  • Contraction of the muscles squeezes the veins, pushing the blood through them.
  • The valves cause the blood to flow in only one direction, back to the heart.
Figure 17
Figure 17 (graphics18.png)

Figure showing capillaries as the transition between arteries and veins

http://en.wikipedia.org/wiki/File:Illu_capillary.jpg

Interactive diagram illustrating arterial and venous structure.

http://www.phschool.com/science/biology_place/biocoach/cardio2/structure.html

Figure 18
Figure 18 (graphics19.png)

Figure

Shows the how valves cause blood to only flow one way though veins

http://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Venous_valve.svg /2000px-Venous_valve.svg.png

Capillaries

  • Capillaries are little more than a single layer or endothelial cells.
  • Capillaries form intricate networks throughout the tissues.
  • They allow water, nutrients and gasses to diffuse out of the blood and waste materials to diffuse into the blood.
  • This exchange occurs between the blood and the interstitial fluid.
  • The interstitial fluid is the fluid surrounding the cells.
  • The blood never comes into contact with the cells.
  • The blood and interstitial fluid exchange material, and the interstitial fluid then exchanges material with the cells.
Veins
  • The intricate networks formed by the capillaries eventually converge to form venules, (small veins)
  • The venules then converge to form veins which return the blood to the heart.
  • Veins only consist of two layers.
  1. The outer layer is made up of connective tissue
  2. The inner layer is made up of endothelial cells.
Valves
  • Once the blood has passed through the capillaries very little blood pressure remains to return blood to the heart.
  • Instead of pressure from the heart veins use a series of valves to force blood to return to the heart.
  • Contraction of the muscles squeezes the veins, pushing the blood through them.
  • The valves cause the blood to flow in only one direction, back to the heart.
Figure 19
Figure 19 (graphics18.png)

Figure showing capillaries as the transition between arteries and veins

http://en.wikipedia.org/wiki/File:Illu_capillary.jpg

Interactive diagram illustrating arterial and venous structure.

http://www.phschool.com/science/biology_place/biocoach/cardio2/structure.html

Figure 20
Figure 20 (graphics19.png)

Figure

Shows the how valves cause blood to only flow one way though veins

http://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Venous_valve.svg /2000px-Venous_valve.svg.png

Veins

  • The intricate networks formed by the capillaries eventually converge to form venules, (small veins)
  • The venules then converge to form veins which return the blood to the heart.
  • Veins only consist of two layers.
  1. The outer layer is made up of connective tissue
  2. The inner layer is made up of endothelial cells.
Valves
  • Once the blood has passed through the capillaries very little blood pressure remains to return blood to the heart.
  • Instead of pressure from the heart veins use a series of valves to force blood to return to the heart.
  • Contraction of the muscles squeezes the veins, pushing the blood through them.
  • The valves cause the blood to flow in only one direction, back to the heart.
Figure 21
Figure 21 (graphics18.png)

Figure showing capillaries as the transition between arteries and veins

http://en.wikipedia.org/wiki/File:Illu_capillary.jpg

Interactive diagram illustrating arterial and venous structure.

http://www.phschool.com/science/biology_place/biocoach/cardio2/structure.html

Figure 22
Figure 22 (graphics19.png)

Figure

Shows the how valves cause blood to only flow one way though veins

http://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Venous_valve.svg /2000px-Venous_valve.svg.png

Valves

  • Once the blood has passed through the capillaries very little blood pressure remains to return blood to the heart.
  • Instead of pressure from the heart veins use a series of valves to force blood to return to the heart.
  • Contraction of the muscles squeezes the veins, pushing the blood through them.
  • The valves cause the blood to flow in only one direction, back to the heart.
Figure 23
Figure 23 (graphics18.png)

Figure showing capillaries as the transition between arteries and veins

http://en.wikipedia.org/wiki/File:Illu_capillary.jpg

Interactive diagram illustrating arterial and venous structure.

http://www.phschool.com/science/biology_place/biocoach/cardio2/structure.html

Figure 24
Figure 24 (graphics19.png)

Figure

Shows the how valves cause blood to only flow one way though veins

http://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Venous_valve.svg /2000px-Venous_valve.svg.png

Differences between arteries and veins

Table 7
Artery Vein
Small lumen Large lumen
Blood under high pressure Blood under low pressure
Valves absent Valves present
Carries blood away from heart Carries blood towards the heart
Carries oxygenated blood except pulmonary artery Carries deoxygenated blood except pulmonary vein

Indigenous Knowledge Systems

Use and symbology of blood and heart in traditional black culture

Fun facts about your heart

  1. The average adult heart beats:
  • 72 times a minute
  • 100,000 times a day
  • 3,600,000 times a year
  • A billion times during a lifetime.
  1. Each day your heart creates enough energy to drive a truck for 32 kilometres.
  2. Your left lung is smaller than your right one to make room in your chest cavity for your heart.
  3. Clench your fist - the size of your fist is more or less the size of your heart.
  4. Laughing is good exercise for your heart. Whenever you laugh, the blood flow in your heart is increased, keeping your heart healthy.

Investigation: Practical investigation of sheep’s heart

Video: Doing a dissection

http://www.hometrainingtools.com/images/videos/Dissection_Video/dissection_flvpl ayer.html?TB_iframe=true&height=390&width=405

Equipment:

Figure 25
Figure 25 (graphics20.wmf)

Table 8
  • 1 sheep heart
  • Cutting board
  • Scalpel
  • textbook
  • Cotton
  • water
  • funnel
  • scissors

1. EXTERNAL

(a)How would you describe the general shape of the heart?

(b)Note the grooves on the surface of the heart. In which direction do they run.

What do you observe in these grooves.

(c)Identify the atria and ventricles. How do they differ from each other in

appearance. What difference do you notice between the atria and ventricles.

2. If the venae cavae are sufficiently long, insert a funnel into the superior vena cava and tie off the inferior vena cava with a piece of cotton . When water is added through the superior vena cave into the right atrium:

(a)What happens to the wall of the right ventricle?

(b)Press the right ventricle. What do you observe?

(c)Release the pressure. What happens?

(d)Now press the left ventricle a few times. What do you notice?

(e)Now attach funnel to one of the pulmonary veins and tie off the others

(if possible). Pour water down the funnel and press the left ventricle.

What do you observe?

(f)Release the pressure and press the right ventricle. What do you observe?

Remove the funnel and tubes.

3. Cut the superior vena cava from the atrium and cut open the wall of the atrium. Dothe same with the pulmonary vein and left atrium.

(a)Describe the appearance of the inner atrial surface.

(b)Determine the position of the pulmonary artery and the aorta by inserting a

glass rod through these vessel into the chambers of the heart.

Name the artery that leaves the right ventricle.

Name the artery that leaves the left ventricle.

4. Make an incision in the right side of the left ventricle from the oblique groove to the a pex of the heart.

(a)What do you observe between the left atrium and left ventricle?

(b)How many flaps do you see?

(c)What is the function of these flaps?

5. Similarly, make an incision in the left wall of the right ventricle from the oblique groove.

(a)How many flaps do you see between the atrium and the ventricle?

(b)What do these flaps collectively form?

6. Compare the muscular walls of the:

(a) atria and the ventricles

(b) left and right ventricles

7. What do you observe between the two halves of the heart.

8. Examine the tendinous cords .

(a)Where are their points of attachment?

(b)What is their function

9. If the pulmonary artery and aorta are long enough, do this question. Using a funnel, pour water into the pulmonary artery and the aorta.

(a)What do you notice?

(b)What do you see at the base of these arteries?

10. Cut the aorta and pulmonary arteries open longitudinally and examine the valves.

(a)How many parts are there to each of these valves?

(b)Compare the walls of the aorta and the pulmonary artery and suggest a

reason for any difference you many find.

Content actions

Download module as:

PDF | EPUB (?)

What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

Downloading to a reading device

For detailed instructions on how to download this content's EPUB to your specific device, click the "(?)" link.

| More downloads ...

Add module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks