3.2 TRANSPORT IN ANIMALS Flashcards
1
Q
State the need for transport systems in multicellular animals
A
- Multicellular animals cells have a long diffusion distance, so diffusion is not efficient
- Multicellular animals have small SA:V ratio
- Multicellular animals have a higher level of metabolic activity
2
Q
Define and describe single circulatory systems
A
- Where the blood flows through heart just once per circulation of the body
- (heart - gills - body)
Blood flows through two sets of capillaries before going back to heart - Blood returns to heart slowly,low pressure
- For animals with low metabolic activity
3
Q
Define and describe double circulatory systems
A
- Where the blood flows through heart twice per circulation of the body
- (heart - lungs - heart - body)
- Blood flows through one set of capillaries before going back to heart
- Blood returns to heart quicker/ higher pressure
- For animals with high metabolic activity
4
Q
Define closed circulatory system
A
- Where blood is maintained inside vessels
5
Q
Define open circulatory system
A
- Where blood is not maintained in vessels
6
Q
State three similarities between open and closed circulatory systems
A
- Both have liquid transport medium
- Both have vessels to transport the medium
- Both have pumping mechanism to move medium around the system
7
Q
State three differences between open and closed circulatory systems
A
- In open : transport medium in direct contact with cells, transport medium pumped into body cavity at low pressure/slowly , has only a few vessels
- In closed : transport medium has no direct contact with cells, transport medium pumped around body at high pressure/quickly , has many vessels with transport medium exclusively enclosed in them
8
Q
State three features of a good transport system
A
1) A pump to create efficient pressure to push transport medium around
2) Exchange surfaces that enable waste/nutrient exchange
3) Vessels to carry transport medium by mass flow
9
Q
Draw the structure of arteries, veins and capillaries
A
10
Q
Describe veins/venules
A
- Blood travels towards the heart
- Blood is at low pressure so thin walls
- Lumen is large to ease the flow of blood
- Valves prevent the backflow of blood
- Thin elastic tissue/thin smooth muscle as NO constriction/recoil
11
Q
Describe arteries/atrioles
A
- Blood travels away from the heart
- Blood is at high pressure so thick walls to withstand it
- Lumen is small to maintain high pressure
- Elastic tissue allows for stretch/recoil for flunctuations neart the heart
- Smooth muscle can contrict to resist flow and reduce rate when needed
12
Q
Describe capillaries
A
- Very thin (one cell thick)
- Lumen very narrow
- Walls are leaky to allow blood plasma and dissolved substances to leave
- Endothelium is flattened to reduce diffusion distance
13
Q
Define plasma
A
- The fluid portion of the blood conatining dissolved substances (e.g CO2,O2,glucose,amino acids,mineral ions,hormones,proteins)
14
Q
Define tissue fluid
A
- The plamsa fluid surrounding cells
15
Q
Define lymph
A
- The plasma fluid held in the lymphatic system
16
Q
Define lymphatic system
A
- System of tubes that return excess tissue fluid to the blood system
17
Q
Define hydrostatic pressure
A
- Pressure that a fluid exerts when pushing on vessel walls
18
Q
Define oncotic pressure
A
- pressure created by the osmotic effect of solutes
19
Q
Describe the movement of fluids
A
1) Blood has relatively high hydrostatic pressure at the arteriol end of the capilaries
2) Thus, blood plasma fluid is pushed out the capilaries tiny gaps into the surrounding cells
3) Plamsa proteins however are too large to be forced out, so are not present in the tissue fluid
4) Exchange occurs across plasma cell surface membrane of cells with the surrounding tissue fluid
5) O2 and nutrients enter the cells, CO2 and waste leaves the cell
6) At the venous end of the capilaries, the hydrostatic pressure is much lower which allows SOME of the tissue fluid to return with the CO2 and waste
7) The rest of the excess fluid goes into the lymphatic system which is returned to the blood
20
Q
Compare the composition of blood plasma,tissue fluid and lymph
A
21
Q
State the effect of hydrostatic pressure of the blood
A
- Pushes plasma fluid out into the tissues
22
Q
State the effect of hydrostatic pressure on tissue fluid
A
- Pushes fluid back into the capilaries
23
Q
State the effect of oncotic pressure on the blood
A
- Pulls water back into the blood (negative value)
24
Q
State the effect of oncotic pressure on tissue fluid
A
- Pulls water into the tissue fluid
25
Compare the relative **hydrostatic** and **oncotic** pressures in the **venule** and **atriole** end of the **capillaries**
- **Arteriole** end has **higher hydrostatic pressure** than **oncotic pressure**, so **fluid** moves **out**
- **Venule** end has a **lower hydrostatic oressure** than **oncotic pressure**, so **fluid** moves **in**
- (Remaining **fluid** returns to **circulation** via the **lymphatic system**)
26
Compare the sides of the **heart**
- **Right** side pumps **deoxygenated blood** from the **body** to the **lungs** to become **oxygenated**
- **Left** side pumps **oxygenated blood** to the rest of the **body**
27
State the pathway of **blood** in the **heart**
Body → Vena cava → Right atrium → Tricuspid atrio-ventricular valve → Right ventricle → Semi-lunar valve → Pulmonary artery → Lungs → Pulmonary vein → Left atrium → Bicuspid semi-lunar valve → Left ventricle → Semi-lunar valve → Aorta → Body
28
Define **cardiac muscle**
- **Muscle** found in the **walls** of the **heart chamber** that **automatically contracts** and **relaxes** without ever **tiring** (**myogenic**)
29
Explain why the **left ventricle** has **thicker cardiac muscle**
- So it can **contract** with **more force** to **push**/**pump blood** at a **higher pressure** so it flow around the **whole body**
30
State how **valves** are **opened**/**closed**
- By **changes** in **pressure** of the **heart chambers**
31
State the formula for **cardiac output**
32
Define **stroke volume**
- The **volume** of **blood pumped** by the heart in **one minute**
33
Define **heart rate**
- A measure of **heart beats** per **minute**
34
Define **cardiac cycle**
- The **contractions** and **relaxations** of **cardiac muscle** that result in **pressure** and **volume changes** that enable the **valves** to maintain a **unidirectional** **flow** of **blood**
35
Draw the **cardiac cycle**
36
Explain what causes **valves** to **OPEN**
- When **pressure** is **higher behind them**
37
Explain **diastole**
- **Atrium** and **ventricle** walls **relax** but **pressure** in the **ventricles** drop **lower** than **pressure** in the **atrium** (due to previous **blood loss**)
- **Atrioventricular valves** thus **open** to allow **blood** to **flood in**
- **Semilunar valves** are **closed** to prevent **blood escaping out**
- **Elastic recoil** allows **chamber volume increase**
38
Explain **atrial systole**
- Both **atria contract** together creating a **SMALL pressure increase**
- Thus, the **atrioventricular valves open** and **blood** is forced into the **ventricles**
39
Explain **ventricular systole**
- Both **ventricles contract** from the **apex**/**base** while the **atria relax**
- The **increased pressure** in **ventricles** result in **closure** of the **atrioventricular valves** and **opening** of the **semilunar valves**
- Thus, **blood** is forced **out** of the **pulmonary artery** and **aorta**
40
Draw a **pressure graph** of the **cardiac cycle**
41
State what the **rate** of **contraction** is determined by
-**Waves** of **electrical activity**
42
Define **sino-atrial node** (**SAN**)
- The **pacemaker** in the **top right atrium**, sends out **waves** of **electrical excitation** at **regular intervals** to **initiate contractions**
43
Define **atrio-ventricular node** (**AVN**)
- The **node** between **atria** and **ventricles** that **delay** the **wave** of **excitation** to ensure the **atria** has **finished contracting**, so **ventricles** can **fill** up with **blood**
44
Define **purkyne tissue**
- **Tissue** that contains **mucle fibres** that **conduct** the **wave** of **excitation** from the **AVN** down to the **septum** between **ventricles**
45
Describe the steps of **electrical excitation** in the **heart**
1) **SAN** generates a **wave** of **electrical impulse** over the **atria**, causing them to **contract** (***P***)
2) A layer of **non-conducting tissue** in the **atrio-ventricular septum** prevents the wave from **crossing** to **ventricles**
3) Instead, the **wave** of **excitation** passes through the **AVN** between both **atria**
4) After a **short delay** form the **AVN**, the **AVN** conducts a **wave** of **excitation** through the **ventricles**, along the **purkyne tissue**, down the **septum** to the **base**/**apex**
5) Here, it **spreads upwards**, over **ventricle walls**
6) **Cardiac muscles** now contract from the **base**/**apex** **upwards**, causing **blood** to be **ofrced** out of the **major arteries** (***QRS***)
46
Define **bradycardia**
- **Slow heart rate**
47
Define **tachycardia**
- **Fast heart rate**
48
Define **ectopic**
- **Early ventricular beat**
49
Define **fibrillation**
- **Atria beats more frequently** than **ventricles**
- **No clear P-waves**
50
Draw a **wave** of **excitation**
(**Normal heart rate**)
51
What is an **electrocardiodiagram** (**ecg**) used for
- To measure **heart rate rythms**
52
State how **oxygen** is transported
- Via the **conjucated globular protein haemoglobin** in **erythrocytes**
53
State the **three** ways **carbon dioxide** is transported
1) **Dissolved** in **plasma**
2) As **haemoglobinic acid** (when carbon dioxide reversibly binds to haemoglobin)
3) As **hydrogen carbonate ions** **HCO3-** (when it joins with water in red blood cells cytoplasm via the catalyst carbonic anhydrase)
54
Define **haemoglobinic acid**
- The compound formed by the **buffering action** of **haemoglobin** as it **combines** with **excess** **hydrogen ions** in **red blood cells**
55
Define **chloride shift**
- The **movement** of **chloride** **ions** into **red blood cells** to **balance** the **charge** as **hydrogen carbonate ions** **leave** the **red blood cells**
56
Define **carbonic anhydrase**
- The **enzyme** that **catalyses** **combination** of **CO2** and **H2O** in the **cytoplasm** of **red blood cells** to form **hydrogen carbonate ions HCO3-**
57
Define **bohr effect**
- When **partial pressure (concentration)** of **CO2** results in **haemoglobin** having a **reduced affinity** for **oxgyen** resulting in **dissociation** of **oxygen**
58
Explain the **bohr effect**
(Effect of **increasing CO2** **concentration** on **haemaglobin**)
- **CO2** enters **red blood cells** and forms **carbonic acid HCO3-** which releases a **H+ ion** when it **dissociates** so **increases** **acidity** of **pH** of **red blood cell**
- The **acidity** now effects the **tertiary structure** of **haemoglobin** and **reduces haemoglobins affinity** for **oxygen**, so **less** is taken up
(Causes the **curved line** to **shift** to the **right**)
59
Draw the formation of **hydrogen carbonate ions HCO3-** in **red blood cells**
60
Compare and explain **fetal** and **adult haemoglobin**
- **Fetal haemoglobin** has a **higher affinity** for **oxygen** because the **placenta** has a **low oxygen partial pressure** (**concentration**) so must be able to take up **oxygen** at low **partial pressures** when **adult haemoglobin dissociates**/**releases oxygen** in the **placentas low oxygen partial pressure**
61
State where **haemoglobins affinity** for **oxygen** comes from
- The **Fe2+ ion**
62
How many **oxygen molecules** can one **RBC hold**
- **Four**
