Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Transport in animals > Flashcards

Transport in animals Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Single Circulatory system (fish)

A
  • DEOXYGENATED blood is pumped by the heart through blood vessels to the GILLS.
  • In the gills, the blood passes through narrow CAPILLARIES.
  • OXYGEN diffuse from the water into the blood.

-OXYGENATED blood now passes from the gills through blood vessels to the BODY TISSUES.

  • The blood then passes through CAPILLARIES where oxygen diffuse from the blood into CELLS.
  • The DEOXYGENATED blood now RETURNS in blood vessels to the HEART.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The role of the CAPILLARIES in a single circulatory system

A
  • When the blood leaves the heart , the PRESSURE of the blood is HIGH and is moving RAPIDLY.
  • However, the blood passes through TWO SETS of capillaries .
  • These DECREASE the flow of blood and REDUCE the PRESSURE.
  • This LIMITS how rapidly oxygen can be delivered to the body cells.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Double Circulatory System (mammals)

A
  • DEOXYGENATED blood is pumped under HIGH PRESSURE from the heart to the LUNGS.
  • In the lungs, the blood passes through CAPILLARIES, reducing the speed and pressure.
  • OXYGEN diffuses from the air into the blood.
  • The OXYGENATED blood now returns back to the heart which pumps the blood at HIGH PRESSURE to the rest of the BODY.
  • As it passes through the body tissues ,the blood passes through CAPILLARIES and OXYGEN diffuses to the body cells.
  • The LOW PRESSURE , DEOXYGENATED blood now makes it way back to the heart to be pumped again.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Advantages of a Double Circulatory System

A
  • The blood moves through the heart TWICE
  • This ensures the blood moves to the tissues RAPIDLY and under HIGH PRESSURE.
  • This allows oxygen delivery to be more EFFICIENT.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

OPEN circulatory system

A
  • In fish and mammals
  • The blood is contained in BLOOD VESSELS when transported.
  • This allows the blood to move relatively RAPIDLY.
  • The AMOUNT of blood passing to different organs can be CONTROLLED by constricting or dilating the blood vessels.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

CLOSED circulatory system

A
  • In insects
  • DO NOT contain blood
  • Insects contain a fluid called HAEMOLYMPH which carries nutrients but it does not carry oxygen.
  • Haemolymph is pumped out of the heart and passes DIRECTLY into the body cavity called HAEMOCOEL.
  • Molecules are transported between the haemolymph and the body cells.
  • The haemolymph then makes its way back to the heart.
  • Haemolymph is NOT carried in vessels therefore is apart of an open circulatory system.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The cardiac cycle

A

The control and coordination of the heart.

3 Stages:
- Atrial systole
- Ventricular systole
- Diastole

systole ~ relaxing
diastole ~ contracting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

1 Atrial systole

A
  • The atria CONTRACT
  • This causes the pressure in the atria to INCREASE.
  • The AV valves open, so the blood flows down into the VENTRICLES.
  • This causes the pressure of the ventricles to INCREASE.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

2 Ventricular systole

A
  • The ventricles CONTRACT
  • The pressure in the ventricles INCREASES (more in the left side).
  • this is because the pressure in the ventricles is now GTREATER than in the atria.
  • The AV valves shut
  • The SEMILUNAR valves in the aorta OPEN because pressure in the ventricles is greater than in the aorta.
  • Blood now flows out of the ventricles through the aorta.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

3 Diastole

A
  • The pressure in the ventricles DECREASES as the blood is LEAVING.
  • At a certain point, the pressure in the left ventricle is LESS than in the aorta.
  • Now the SEMILUNAR valves close preventing blood being drawn back into the left ventricle
  • While the ventricle was CONTRACTING, the left atrium was RELAXING.

-This means that blood was flowing into the atrium from the vena cava and pulmonary vein.

  • The ventricle now starts to RELAX, causing pressure in the ventricle to FALL, eventually below the pressure in the atria.
  • This causes the AV valves to open and blood flows into the ventricle from the atrium.
  • As the atria and ventricles refill , the heart is now ready to enter the next cardiac cycle.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Blood volume during the cardiac cycle

A
  • INCREASES as it is pumped into the left ventricle when the left atrium contracts.
  • DECREASES when the left ventricle contracts as blood passes out the aorta.
  • INCREASES AGAIN as the left ventricle relaxes and blood flows down from the left atrium.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Initiation and Coordination of the action of the heart

A
  • The heart beat is initiated from WITHIN the heart itself.
  • The heart does not need an EXTERNAL SIGNAL in order to beat.
  • Because the heart triggers its own beat , it is described as MYOGENIC.
  • There are two nodes in the heart:
    • Sino-atrial node
    • Atrio-ventricular node
  • Electrical impulses are sent from the SAN to the AVN coordinating heart muscle contractions.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The role of the SAN

A
  • In the wall of the RIGHT ATRIUM there is a group of specialised cells called the SINO-ATRIAL NODE.
  • This is also called the PACEMAKER.
  • The cells in the SAN DEPOLARISE (they become electrically excited.

-This triggers a wave of electrical excitation to spread across the ATRIA.

  • This causes the atria to contract ~ ATRIAL SYSTOLE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why cant the wave of electrical excitation crossing the atria pass DIRECTLY down to the ventricles?

A
  • The ventricles are separated from the atria by a layer of NON-CONDUCTING TISSUE.
  • This layer of tissue will NOT pass the electrical excitation through it.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The role of the AVN

A
  • Between the ATRIA there is another group of specialised cells called the ATRIO-VENTRICULAR NODE.
  • The AVN is connected to the conducting fibres called PURKYNE FIBRES.
  • The AVN detects the electrical excitation passing over the atria.
  • After a SHORT DELAY, the AVN then transmits the electrical excitation down the PURKYNE FIBRES.
  • This electrical excitation causes the ventricles to contract from the apex upwards ~ VENTRICULAR SYSTOLE.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The purkyne fibres

A

-The AVN is connected to these conducting fibres .

  • Initially these fibres are bundled together so are described as the BUNDLE OF HIS.
  • However , this then BRANCHES , with purkyne fibres running down to the APEX or BASE of the heart and then up the walls of the VENTRICLES.
17
Q

Why do the ventricles contract from the apex upwards?

A

To ensure that the MAXIMUM VOLUME of blood is pumped out of the ventricles.

18
Q

Why is there a slight delay before the AVN triggers the electrical excitation down the purkyne fibres?

A

To ensure that the ventricles contract AFTER the atria have contracted.

19
Q

Polarisation and depolarisation

A
  • The MEMBRANES around the two nodes, allow a CHARGE to be maintained across the membrane.
  • At REST the nodes become POLARISED.
  • A POSITIVE charge builds up on the INSIDE of the node , and a NEGATIVE on the outside.
  • This is caused by IONS building up.
  • When CONTRACTION occurs, the nodes are DEPOLARISED.
  • Positively charged ions move out oof the nodes STIMULATING a move in electrical electricity in the heart.
20
Q

An electrocardiogram

A
  • By attaching ELECTRODES to the surface of the skin, scientists can analyse the ELECTRICAL ACTIVITY of the heart.
  • The resulting TRACE is called an electrocardiogram or an ECG.
21
Q

Calculating the Heart Beats Per Minute.

A
  • Pick an interval on the graph which begins and ends at equivalent points in a heart beat.

60/ value of ones space x number of spaces in that interval

x number of peaks in that interval

22
Q

Bradycardia

A
  • When the heart rate drops below 60 BPM.

ATHLETIC TRAINING:
This increases the STROKE VOLUME of the heart meaning the heart pumps a greater blood volume per beat, so the number of BPM decreases.

DISEASE:
May require an artificial pacemaker.

23
Q

Tachycardia

A
  • When the heart rate is greater than 100 BPM.

SHORT TERM:
-Fear
-Panic
-Exercise

LONG TERM:
- Caused by problems with the sinoatrial
node or other medical conditions.
- Requires surgery or drugs

24
Q

Ectopic heart beat

A
  • An EXTRA heart beat that is not part of the hearts usual rhythm.
  • The heart contracts again BEFORE the first contraction has finished.
  • This is followed by a SHORT PAUSE before the normal rhythm continues.
  • Relatively COMMON and does not pose any health risks.

-However, if experienced more frequently, this may indicate a more serious heart condition.

25
Q

Atrial fibrillation

A
  • IRREGULAR waves of electrical excitation pass over the atria.
  • This causes the atria to contract RANDOMLY & RAPIDLY. (up to 100BPM)
  • In most cases, the electrical excitation is not transmitted to the VENTRICLES.
  • This means the ventricles contract LESS FREQUENTLY than the atria.
  • Because the normal rhythm of the heart is disrupted it is considered a type of ARRHYTHMIA.
26
Q

Arteries : STRUCTURE related to FUNCTION

A

THICK WALL:
- allows the artery to withstand high pressure of the blood.
- The wall consists of several layers.

OUTER LAYER:
- Rich in the fibrous protein collagen.
- Collagen plays a structural role, strengthening the artery wall against the pressure of blood.

SECOND LAYER:
- Contains smooth muscle.
- This contracts , narrowing the diameter of the arteries.
-This allows the body to control how much blood flows to different organs.
- Smaller arteries tend to contain a greater proportion of smooth muscle compared to larger arteries as they play a bigger role in controlling blood flow.

THIRD LAYER :
- Rich in elastic fibres which contain the protein elastin which can stretch.
- When the elastic fibres recoil it helps to keep the blood moving smoothly forward on between contractions of the heart.

CENTRAL CAVITY ~ LUMEN:
- Where the blood flows through
- Lined with a thin layer of endothelial cells.
- This presents a very smooth surface to reduce friction as the blood flows through.

27
Q

Arterioles

A
  • Their walls contain the SAME layers as arteries but they differ in relative THICKNESS.

THINNER collagen & elastic layer:
- This is because the blood pressure is lower than in arteries and the effect of the pulse is weaker.

THICKER smooth muscle layer:
- This is because they are involved in controlling the amount of blood passing through the capillaries.

VASOCONSTRICTION ~ when smooth muscle contacts and blood flow in capillaries is reduced.

VASODILATION ~ when smooth muscle relaxes and blood flow in capillaries increases.
This takes place when an organ requires an increased amount of carbon dioxide.

28
Q

How has the STRUCTURE of CAPILLARIES evolved to maximise the rate of DIFFUSION?

A

EXTENSIVE BRANCHING:
- Provides a massive SA for the exchange of materials.

EXTREMELY THIN WALL:
- Consists of a single layer of endothelial cells.
- Creates a short diffusion distance between the blood and the cells nearby .

LUMEN ONLY SLIGHTLY LARGE THAN THAT OF A RED BLOOD CELL:
- When red blood cells pass through they are pressed against the capillary wall.

  • This reduces the distance for the diffusion of oxygen from red blood cells to the tissue cells.
  • This also means red blood cells move single file, slowing down their movement which increases the time available for molecules to diffuse in and out of the blood.

SMALL GAPS BETWEEN THE ENDOTHELIAL CELLS:
- Tissue fluid,, which bathes cells and provides essential molecules, can pass out of the blood.

  • Also allow white blood cells to leave through the bloodstream.
29
Q
A

Biology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions