3.1 EXCHANGE SURFACES Flashcards
(58 cards)
1
Q
State the SA:V of single celled organisms
A
- High surface area to volume ratio
2
Q
State and explain how single celled organisms obtain nutrients/gases
A
- Via simple diffusion
- Because they have large SA:V ratios
- So short diffusion distance for maxiumum absorbtion
3
Q
State the SA:V of large organisms
A
- Low surface area to volume ratio
4
Q
State the formula for surface area:volume ratio
A
SA:V = Surface area(cm2) ÷ Volume(cm3)
5
Q
State what more metabolic organisms require
A
- ENERGY from food and oxygen to release energy in the form of ATP in aerobic respiration
- Energy to keep them warm
6
Q
State and explain three features of a good exchange surface
A
1) Large surface area to enhance the space molecules can pas through
2) A thin barrier to reduce the diffusion distance
3) A good blood supply to maintain a concentration gradient and bring in molecules
7
Q
Define alveoli
A
- Tiny folds in the lung epithelium to increase surface area
8
Q
Describe bronchioles
A
- Smaller, smooth muscle airways leading to the lungs
- Has no cartilage
- Made of smooth muscle sp can contrict and dilate to controll airway airflow
- Narrow with thin walls so some exchange may occur
9
Q
Describe bronchi/bronchus
A
- Smaller than trachea but larger than bronchioles
- Thin walls with a smaller diameter than the trachea
- Have a full ring of cartilage
10
Q
Define diaphram
A
- A layer of muscle between the lungs
11
Q
Define intercoastal muscles
A
- Muscles between the ribs
- Contraction of the intercoastal muscles raise the ribcage
12
Q
Describe trachea
A
- The main airway leading from the back of the mouth to the lungs
- Has C-shaped cartillage rings to prevent friction with the asophagus behind
- Has cillitaed epithelial cells to waft microbes to filter airways
- C-shaped cartillage also prevents collapse
- Has goblet cells that produce mucus to capture dust and microbes
13
Q
Define ventilation
A
- The refreshing of air in the lungs so that there is a higher oxygen concentration than in the blood and a lower carbon dioxide concentration than in the blood
- (Thus, gaseous exchange occurs)
14
Q
Draw the structure of the lungs
A
15
Q
Describe inhalation
A
1) External intercoastal muscles contract so that the ribs move up and out
2) The diaphram contracts to move down and flatten
3) Therefore, the volume of the chorax/chest cavity increases
4) The pressure in the thorax drops down below atmospheric pressure
5) So, air is drawn in
6) ACTIVE PROCESS
16
Q
Describe exhilation
A
1) External intercoastal muscles relax so that the ribs move down and inwards
2) The diaphram relaxes also and becomes dome shaped
3) Therefore, volume in the thorax/chest cavity decreases
4) Pressure inside the thorax/lungs increases above atmospheric pressure
5) So, air is drawn out
6) PASSIVE PROCESS
17
Q
State five features of the alveoli
A
1) Large surface area
2) Exchange barrier is permeable to oxygen and carbon dioxide
3) Thin barrier to reduce diffusion distance
4) A good blood supply
5) Elastic fibres
18
Q
Explain the large surface area of the alveoli
A
- Provides more space for molecules to pass through
- Also lined with a layer of moisture so gases can dissolve for more efficient diffusion
- Internal layer of the alveoli is coated in a surficant that reduces cohesion between water molecules
19
Q
Explain the exchange barrier permeability of the alveoli
A
- The cells of the alveoli/capillaries and their plasma cell surface membranes are permeable to oxygen and carbon dioxide
- Because they are small and non polar molecules
20
Q
Explain the thin barrier of the alveoli
A
- Reduces the diffusion distance
- Alveoli and capillaries are one cell thick
- Both walls are squamous
- Alveoli and capillaries are in close contact
21
Q
Explain the good blood supply of the alveoli
A
- Helps maintain a steep concentration gradient so carbon dioxide diffuses out and oxygen diffuses in
22
Q
Explain the elastic fibres of the alveoli
A
- Allows dilation of the alveoli as air is drawn in to maximise space
23
Q
Define cilliated epithelium
A
- A layer of cells that have many hair like cilia
24
Q
Define elastic fibres
A
- Protein fibres that can deform and recoil to dilate the alveoli
25
Define **goblet cells**
- **Cells** that **secrete mucus**
26
Define **smooth muscle**
- **Involuntary muscle** that **contracts** without the need of **conscious thought**
27
Define **buccal cavity**
- A **fish mouth**
28
Define **fillament**
- **Branches** of **tissue** that make up the **gill** (aka **primary lamellea**)
29
Define **lamellea**
- (Aka **secondary lamellea** or **gill plates**)
- Are **folds** in the **fillament** to **increase surface area** and is the **site** of **gas exchange**
30
Define **operculum**
- A **bony flap** that **covers** and **protects** the **gills**
31
Define **counter current flow**
- Where **blood** and **water flow** in **opposite directions**
32
Describe the **counter current exchange** of **bony fish**
- **Blood flows** along the **gill arch** and out along the **fillament** to the **lamellea**
- The **blood** then flows through **capillaries** in **opposite direction** to the flow of **water** over the **lamellea**
- The **countercurrent flow absorbs** the **maximum** amount of **water**
33
Describe **ventillation** in **bony fish**
- The **buccal cavity** can **change volume**
- The **floor** of the **mouth moves downwards** which **decreases** the **pressure** and **draws** in more **water**
- The **mouth** **closes** and the **floor** is **raised again**, **pushing water** through the **gills**
- As **water** is **pushed** from the **buccal cavity**, the **operculum moves outwards**
- This movement **decreases pressure** in the **opercular cavity**, helping **water** flow to the **gills**
34
State the **three** ways **large insects** can **ventilate**
1) **Movement** of the **wings** - (alters **thorax volume**)
2) **Expansion** of **tracheal system** - (expand **air sacs**)
3) Locusts **specialised breathing movements** (**air** control via **valves**)
35
Draw the structure of an **insect**
36
Draw the structure of **insect tracheoles**
37
State the **circulatory system** of **insects**
- **Open circulatory system**
- **Slow circulation** and can be affected by **body movements**
38
Describe the **exchange** of **insects**
- **Air** enters via **spirical pores** through to the **tracheae tubes**
- Then through to **smaller tracheoles** which are **open ended** and filled with **tracheal fluid**
- **Gaseous exchange** occurs between the **air** in the **tracheoles** and the **tracheal fluid**
39
Describe **exchange** in **insects** with **high metabolic activity**
- **Tracheal fluid** gets **withdrawn** into the **body fluid** in order to **increase** the **surface area** of the **tracheole wall** that is **exposed** to **air**
- This means that **more oxygen** can be **absorbed** when the **insect** is **active**
40
Describe the **movement** of **insect wings** on **ventillation**
- **Alters** the **thorax volume**
- As the **thorax volume decreases**, **air** in the **tracheal system** is put **under pressure**
- Therefore, its **pushed out** of the **tracheal system**
- When the **thorax volume increases**, the **pressure** inside the **thorax decreases**
- Therefore, **air** is **pushed into** the **tracheal system** from **outside**
41
Describe the **expansion** of **insect tracheal system** on **ventilation**
- **Tracheal expansion** occurs to **increase flexibility** of the **walls**
- These act as **air sacs** which can be **squeezed** by the action of **flight muscles**
- **Repetative expansion** and **contraction** of these **sacs ventilate** the **tracheal system**
42
Describe the **abdomine volume alteration** of **insects** on **ventillation**
- **Abdomine volume alteration** is co-ordinated by **opening** and **closing valves** in the **spiricals**
- As the **abdomine expands**, **spiricals** at the **front end** of the body **open** and **air enters** the **tracheal system**
- As the **abdomine reduces** in **volume**, the **spiricals** near the **end** of the body **open** and **air** **leaves** the **tracheal system**
43
Define **breathing rate**
- The **number** of **breaths** per **minute**
44
Define **oxygen uptake**
- The **volume** of **oxygen absorbed** by the **lungs** in **one minute**
45
Define **spirometer**
- A device that can measure the **movement** of **air** **into** and **out** the **lungs**
46
Define **vital capacity**
- The **maximum volume** of **air** that can be **expelled** from the **lungs** after taking **deepest possible breath**
47
Define **tidal volume**
- The **volume** of **air inhaled** or **exhaled** in **one breath**, usually measured at **rest**
48
Define **residual volume**
- The **volume** of **air** that **remains** in the **lungs** after **forced exhilation**
- (Remains in the **airways** and **alveoli**)
- (Aprox. **1.5dm3**)
49
Draw a labled **spirometer**
50
State **precautions** to take with **spirometers**
- The **subject** should be **healthy/asmtha free**
- The **soda lime** should be **fresh/functioning**
- There should be **no air leaks** in the **apparatus** (**invalid/inaccurate result**)
- The **mouthpeice** **steralised**
- The **water chamber** must not be **overfilled** (or **water** may enter **air tubes**)
51
State **three** factors that **vital capacity** depends on
1) The **size** of the **person** (particularly **height**)
2) Their **age/gender**
3) Their **level** of **exercise**
52
State the **average vital capacity**
- **2.5dm3** to **5.0dm3**
53
State the **average tidal volume**
- **0.5dm3**
54
Draw a labled **spirometer trace**
55
State an assumption about **oxygen uptake**/**CO2 removal**
- That the **volume** of **carbon dioxide absorbed** by the **soda lime** is equal to the **oxygen uptake** into the **blood**
56
Describe how to calculate **oxygen uptake** from a **spirometer trace**
57
State how to measure **breathing rate** from a **spirometer trace**
- **Count** the **number** of **peaks** in **each minute**
58
State **two** factors explain **increased oxygen uptake**
- **Increased breathing rate** (excercise)
- **Deeper breaths** (excercise)
