Chapter 4 - gas exchange and excretion Flashcards

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1
Q

What is gas exchange in humans

A

The take in of oxygen and the removal of carbon dioxide

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2
Q

Where does gas exchange occur in humans

A
  • In humans, gas exchange occurs in the alveoli in the lungs
  • Gas exchange occurs via diffusion
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3
Q

What parts are used to move air in the alveoli

A

They move alongthe trachea and the bronchi and bronchioles

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4
Q

How does deoxygenated blood move to the alveoli

A

It moves along capillaries that branch from the pulmonary artery

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5
Q

How does oxygenated blood move from the alveoli

A

Along the capillaries that join up to the pulmonary vein

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6
Q

How does oxygen diffuse from the alveoli to the blood

A
  • Capillaries lie close to the walls of the alveoli
  • oxygen diffuses form the air inside the alveoli into the capillaries
  • this occurs because the concentration of oxygen is higher inside the air in the alveoli than in the deoxygenated blood
  • Hence there is a diffusion gradient for oxygen, from the alveoli to the blood
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7
Q

Why does carbon dioxide diffuse from the blood into the air inside the alveoli

A
  • Because the concentration of carbon dioxide is higher in the deoxygenated blood than in the air inside the alveoli
  • Thereofre, there is a diffusion gradient for carbon dioxide, from the blood into the alveoli
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8
Q

Which features allow maximum gas exchange to occur

A

Large surface area - faster diffusion

Thin walls - short diffusion distance

Good ventilation with air - so diffusion gradients are maintained

Good blood supply - To maintain a high concentration gradient so diffusion occurs faster

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9
Q

Describe the diagram of gas exchange

A
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10
Q

Why are the alveoli kept moist

A

To stop them from drying out

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11
Q
A
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12
Q

Label this

A
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13
Q

What is the role of the ribs

A

Its a bone structure that protect vital organs

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14
Q

What is the role of interocstal muscles

A

Muscles between ribs which control their movement causing inhalation and exhalation

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15
Q

What is the role of the diaphram

A

Sheet of connective tissue and muscle at the bottom of the thorax that helps change the volume of the htorax to allow inhalation and exhalation

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16
Q

What is the role of the trachea

A

It is a windpipe that connects the lungs with the mouth and nose

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17
Q

Role of the larynx

A

The voice box; when air passes across the larynx a sound is made

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18
Q

What is the role in bronchi

A

large tubes branching of the trachea with one bronchus for each lung

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19
Q

Role of the bronchioles

A

Bronchi split to form bronchioles in the lungs which connect to alveoli

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20
Q

What is the role of alveoli

A

They are tiny air sacs where gas exchange takes place

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21
Q
A
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22
Q

Features of the trachea and their functions

A

Rings of cartilidge surround the trachea to provide support for the airways and to keep them open during breathing

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23
Q

What are goblet cells

A

Cells that secrete mucus

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24
Q

What are cilia cells

A

Cells covered in tiny hairs called cilia

  • They are used to beat and push mucus out of the lungs into the throat
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25
Q
A
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26
Q

How does cilia and mucus work together

A
  1. Bacteria and small particles in the air are trapped in the sticky mucus
  2. The cilia wave in unison, pushing the mucus up towards the back of the throat where it is swallowed
  3. This prevents bacteria and small particles entering the lungs and causing infection
27
Q

What is the definition of a breathing movement

A

The movement of air in and out of the lungs

28
Q

What happens in inspiration (muscles)

A
  • Muscles in the diaphragm contract, pulling the diaphragm upwards
  • The external intercostal muscles contract pulling the ribs upwards
  • These increase the volume in the thorax
  • pressure in the thorax decreases
  • air from the outside of the body flows down the trachea into the thorax, from higher pressure outside the thorax to lower pressure inside
29
Q

What happens in expiration (muscles)

A
  • The muscles in the diaphragm relax, pulling it up
  • The external intercostal muscles relax, allowing the ribs to move down
    • These decrease the volume of the thorax
  • The pressure of the htorax increases
  • Air from inside the body flows out of the thorax up the trachea, from higher pressure to lower pressure inside the thorax to the lower pressure region inside it.
30
Q

In inspiration and expiration, what are the internal and external intercostal muscles

A

Antagnostic, they do the opposite

31
Q

What is the gas composition of inspired air

A
  • Oxygen - 21%
  • Carbon dioxide - 0.04%
  • Water vapour - variable
32
Q

What is the compositon of expired air

A
  • Oxygen - 16%
  • Carbon dioxide - 4%
  • Water vapour - high
33
Q

How does nitrogen compare from inspired ot expired air

A

Stays at 78%

34
Q

Describe and make a diagram for a test to show more CO2 is present in expired air

A
  • When we breath in the air is drawn through boiling tube A
  • Breath out, air drawn through boiling tube B
  • Limewater in A remains clear, boiling tube B turns cloudy
  • Shows the CO2 is more present in expiration
35
Q

What happens to the rate and depth of breathing within heavy excercise

A

Breathing is faster and deeper - so you can get more air to your working muscles, and remove the co2 they produce during excercise

36
Q

What happens when there is a higher carbon dioxide concentration in the blood

A
  • The carbon dioxide concentration stimulates recpetor cells in the brain
  • The brain sends impulses to the muscles of the lungs to contract faster and more strongly
  • This causes the depth and frequency of breathing to increase
37
Q

What is the energy from respiration used for

A
  • Muscle contraction
  • Building protein molecules
  • cell division
  • sending electrical impulses
  • keeping body tempurature constant
  • active transport of substances
38
Q

Definition of aerobic respiration

A

The chemical reactions in cells that use oxygen to break down nutrient molecules to release energy

39
Q

What does respiration involve

A

The action of enzymes in cells

40
Q

Describe an experiment to investigate the uptake of oxygen in aerobic respiration

A
  • As the organisms anaerobically respire, they take in oxygen and give out carbon dioxide
  • the carbon dioxide is absorbed by soda lime
  • the volume of air therefore decreases in the syringe barrel
  • this causes the drop of liquid to move along the capillary tube towards the organisms
  • The fatser the rate of respiration, the faster the drop moves along the capillary tube
41
Q

Definition of anaerobic respiration

A

The chemical reactions in cells that break dwon nutrient molecules to release energy without using oxygen

42
Q

What are the two word equations for anaerboic respiration

A
  • Glucose –> Lactic acid
  • Glucose –> Alchahol and carbon dioxide
43
Q

What is the balanced equation for anaerobic respiration

A

C6H12O6 —> 2C2H5OH + 2CO2

44
Q

What is an oxygen debt and how does it occur

A
  • When a person does vigorous excercise, contracting muscles use oxygen to release energy in aerobic respiration
  • The extra oxygen isn’t enough to allow the muscles to release all of the energy, therefore the muscles use anaerobic respiration to top up the energy release
  • Lactic acid produced builds up in muscle cells, diffuses into the blood, and is transported to the liver, faster heart rate speeds this up
  • Liver cells break down the lactic aicd by combining it with oxygen, this occurs for some time after the excercise, this is oxygen debt
  • *
45
Q

Where is carbon dioxide excreted from?

A

The lungs

46
Q

Where is urea produced and excreted

A

It is produced in the liver and excreted through the kidneys

47
Q

Where are excess salts and water excreted from

A

The kidneys

48
Q

What is the volume and concentration of urine produced by the kidneys affected by

A
  • How much liquid you have drunk; the more water you take in the more urine
  • How hot is it, or how much excercise you do; the hotter you are, the more water you lose in sweat, the less water will be in your urine
49
Q

What is the liquid produced by the liver, and how does it get to where it is stored

A

Urine is produced in the liver and flows down two ureters, is stored in the bladder, and leaves the body through the urethra

50
Q

What are the roles of the liver

  • (think nitrogen)
A
  • When protein in foods is digested to amino acids, the amino acids are transported to the liver in the blood in the heptic vein
  • In the liver - some of the amino acids are built into proteins, such as plasma protein fibrinogen
  • In the liver - the excess amino acids are broken down to urea by deamination
51
Q

What is the definition of deamination

A

The removal of the nitrogen-containing part of amino acids to form urea

52
Q

Why must urea be removed

A

Urea is toxic and too much accumulated would harm the cells in the body

53
Q

Which part of the kidneys produce urine

A

Nephrons - tiny little tubules

54
Q

Identify - the kidney, ureter, bladder and urethra

A
55
Q

Why must excretion take place

A

To get rid of toxic chemicals like urea and carbon dioxide

56
Q

Label the kidney tubule

A
57
Q

What is dialysis

A

The passing of a person’s blood through a machine in which the blood is spearated from dialysis fluid by a partially permeable membrane

58
Q

What does dialysis fluid contain and why are their concentrations ideal?

A
  • It contains water, salts and glucose
  • The concentration is ideal as it is the same as human blood
  • The dialysis fluid does not contain urea
59
Q

Dialysis - what happens as blood flows through the machine

A
  • Urea in the blood diffuses from the blood into the dialysis fluid, down its concentration gradient via the membrane
  • Glucose either diffuses into or out of the blood, depending if its concentration is higher or lower than the dialysis fluid
  • water moves by osmosis either in or out of the blood, depending if the water potential is higher or lower than in the dialysis fluid
60
Q

Disadvantages of dialysis

A
  • Expensive
  • Highly trained proffessionals can only use it properly
  • the person must be linked up to the machine regularily for several hours at a time
  • the

in between treatments the concentration of urea and other toxic substances may damage body tissue

61
Q

What is the alternative to dialysis

A

A kidney transplant -

  • However kidneys are in short supply
  • Even if the cell types are a good match, the person recieving the kidney will need to take immunodepressant drugs for the rest of his life, leaving them vulnerable to infectious disease
62
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63
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