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human bio semester 1 exam Flashcards

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1
Q

define metabolism

A 
All the chemical reactions/processes that take place 
in the cells/body
•	2 main types:
	Anabolic: 
          o	Building/synthesising
          o	Using smaller molecules to build/make larger 
                 molecules
          o	E.g. protein synthesis
Catabolic:
      o	Breaking down larger molecules into simpler 
            molecules
      o	E.g. digestion (releases energy)

• This is done using enzymes

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2
Q

what are enzymes (structure, role)

A

organic catalysts: speed up rate of reaction and lower activation energy

specific proteins

Have an activation site: specific site that will only combine with specific molecules (substrate)

Substrate: molecule on which enzyme acts upon

lock and key model:
- enzymes are specific & fit together perfectly, like a lock
and key
- enzyme is like a specific key shaped to fit the lock
(substrate) and only the correct enzyme can connect
with the substrate

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3
Q

what is cell respiration

A

Complex chemical reactions that take place in the cells cytoplasm and mitochondria (cristae)

Process of converting glucose to a usable form of energy (ATP) + heat

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4
Q

Explain what happens during the stage of glycolisis

A

doesn’t require oxygen or energy

occurs in cytoplasm

breaks down 1 glucose molecule into 2 pyruvate molecules

produces 2 ATP

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5
Q

Explain what happens during the stage of Anaerobic respiration

A

occurs when oxygen is not available e.g. during exercise

occurs in cytoplasm

breaks down 2 pyruvate molecules into 2 lactic acid molecules produced through fermentation

energy from glycolysis converts 2 ADP into 2 ATP

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6
Q

Explain what happens during the stage of Aerobic respiration

A

occurs in mitochondria

step 1:
pyruvate molecules enter mitochondria
pyruvate is converted into acetyl CoA (1 carbon dioxide is removed & remaining 2-carbon structure joins to coenzyme A)

step 2:
acetyl CoA enters Krebs cycle
carbon atoms in acetyl CoA produces carbon dioxide and hydrogen ions
2 ATP produced

step 3:
uses oxygen
enters electron transport system: electrons are passed along electron transfer chain, hydrogen ions eventually collide with carbon dioxide and water is produced
produces 24 ATP

26 - 34 ATP produced **theoretical maximum

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7
Q

explain the 7 factors affecting enzyme activity

A
  1. concentration of enzyme: higher concentration of enzymes, faster rate of reaction because more enzymes present
  2. concentration of substrate: increasing substrate concentration increases rate of reaction because more substrates contact enzymes
  3. temperature: rate of reaction increases as temperature increases within optimum range (30 - 40˚) or enzyme denatures
  4. pH: each enzyme has an optimum pH where it’ll work most effectively
  5. products must be continually removed: or rate of reaction will slow because it’ll be more difficult for substrates to contact enzymes
  6. presents of cofactors of coenzymes: ions of non-proteins molecules that catalyse reactions.
    cofactors: change shape of active site so enzyme can contact substrate
    coenzyme: non-protein organic molecule e.g. vitamins
  7. enzyme inhibitors: slow or stop reactions, controls the amount of products produced
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8
Q

explain what ‘nutrients’ is

A

Substances found in food required by cells for growth, repair & cell functioning

Food contains large complex molecule too big to enter and be used in cells

food must be digested to access nutrients

Organic nutrients/compounds: contain carbon e.g. carbohydrates, protein, lipids

Inorganic nutrients/compounds: vitamin, minerals, water

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9
Q

what are the functions of the digestive system

A
  1. Ingestion: physical process of taking food into the
    body
  2. Movement: muscle contractions move the molecules
    along the alimentary canal
  3. Mechanical digestion: break up of larger particles
    into smaller particles
  4. Chemical digestion: break down of molecules from
    complex particles into its simplest form
  5. Absorption: Simplest form of nutrients move from
    the small intestine into the bloodstream
  6. Elimination: formation of faeces to remove unwanted
    materials from the body
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10
Q

describe the alimentary canal

A
  • Tube that connects mouth to anus
  • All structures that nutrients travel through

• E.g. mouth, pharynx, oesophagus, stomach, small
intestine, large intestine, anus

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11
Q

what are accessory organs

A
  • Structures that are outside the alimentary canal
  • Play a role in digesting the nutrients
  • E.g. salivary glands, liver, pancreas, gall bladder
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12
Q

what are the 2 types of digestion

A
  1. Mechanical: physical process of breaking up larger
    particles into smaller ones
  2. Chemical: chemical process of breaking up complex
    molecules/nutrients into its simplest form e.g.
    enzymes
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13
Q

explain digestion in the mouth

A

pHl neutral to slightly acidic (6 - 7)

mechanical digestion:
mastication: action of the jaw and teeth breaking up food into smaller piece

teeth:
4 incisors: chisel shaped, biting & cutting
2 canines: tearing food
4 premolars: crushing & grinding food
6 molars: broad crowns for crushing & grinding food

tongue pushes bolus toward pharynx for swallowing

chemical digestion:
Salivary amylase is secreted by 3 pairs of salivary glands

Breaks down complex starch into polysaccharides

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14
Q

describe digestion in the stomach

A

pH: highly acidic (2 - 3)

mechanical digestion:
Waves of muscular contraction churns food to create a thick, soupy liquid called chyme

chemical digestion:
Pepsin is secreted from gastric glands

Hydrochloric acid breaks down bacteria and provides optimum pH for pepsinogen

When pepsinogen comes into contact with HCl it is converted into pepsin (active)

Pepsin breaks down complex proteins into polypeptides

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15
Q

describe digestion in the duodenum

A

pH: alkaline (7-8)

(no mechanical digestion)

chemical digestion:
**liver produces bile: bile salts neutralise stomach acid & emulsify fats

Pancreas produces pancreatic juice secreted pancreatic duct:
• Pancreatic amylase: breaks down polysaccharides
into disaccharide
• Trypsin: breaks down polypeptides into dipeptides
• Pancreatic lipase: breaks down fats into fatty acids
and glycerol
• Ribonuclease and deoxyribonuclease: breaks down
RNA and DNA

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16
Q

describe digestion in the ileum and jejunum

A

pH: slightly alkaline (7-8)

(no mechanical digestion)

chemical digestion:

  • *most food absorption occurs here
  • *liver produces bile: bile salts neutralise stomach acid & emulsify fats
  • *6-7 m long

Intestinal glands produce:
• Intestinal amylase: breaks down disaccharides into
monosaccharides
• Intestinal peptidase: breaks down dipeptides into
amino acids
• Intestinal lipase: breaks down fat into fatty acids and
glycerol

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17
Q

describe digestion in the large intestine

A

• 1.5m long
• No digestion or enzymes: water is absorbed
• 18 – 24 hours
• Glands secrete mucous
• Bacteria breaks down any remaining organic
compounds
• Vitamins produced by bacteria are also
absorbed

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18
Q

explain the process of defecation

A

Removal of metabolic waste producesdby chemical
activity of the cells

Referred to as elimination

Faeces contain:
- Water
- Undigested food material
- Bacteria
- Bile pigments
- Remains of cells broken away from alimentary canal 
  lining
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19
Q

explain absorption in the small intestine

A

Occurs through Villi:
- small, finger-like projections from the wall of the small
intestine

  • Microvilli cover each villus to increase surface area for
    absorption
  • Villi are one cell thick and 1 mm long
  • Villi are constantly moving to come into contact with the
    nutrients
  • Inside each Villus is a lymph capillary (lacteal)
    surrounded by a network of blood capillaries
  • Absorption occurs through simple diffusion & active
    transport
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20
Q

explain different nutrients absorption into the bloodstream

A

Fatty acids, glycerol & fat soluble vitamins:
- Enter the lacteal via simple diffusion
- In the villi cells the fatty acids and glycerol combine to
form tiny fat droplets that then enter the lacteals

Amino Acids
- Absorbed into blood capillary network by simple
diffusion

Simple Sugars (e.g. glucose)
- Absorbed into blood capillary network by active 
  transport

Water and water soluble vitamins:
- Enter blood capillary network via simple diffusion

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21
Q

define excretion

A

Process of removing all metabolic waste products from the body

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22
Q

give examples of metabolic waste

A

Heat: remove through skin

Carbon dioxide: removed through lungs

Salts: skin

Lactic acids: kidneys

Bile pigments: alimentary canal

Urea: kidneys

Water: lungs and skin

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23
Q

explain the function of skin in the excretory system

A

Provide protective covering over surface of the body

Regulate body temperature

Plays important role in excretion
- Sweat gland are located in lower layers of skin
- A duct carries the sweat to a hair follicle or skin surface
where it opens at a pore
- Cell surrounding the glands are able to contract and
squeeze the sweat to the surface
- Glands secrete about 500mL water per day
- Dissolved in it are:
o Sodium chloride
o Urea
o Lactic acid
o Some drugs e.g. salicylic acid

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24
Q

explain the process of deamination

A

occurs in the liver (located in upper abdominal cavity)

Metabolic process that breaks down excess protein so it can be excreted

Part 1:
- Excess proteins are broken down in the liver into
amino acids
- The NH2 amino group is removed from the amino acid
- The NH2 group is converted into ammonia

Amino acid + oxygen ——enzymes—-> carbohydrate + ammonia

Part 2:

  • The remains of the amino acid (carbon - hydrogen structure) is converted into a carbohydrate which is used to release energy, CO2 and water
  • Ammonia is highly toxic to cells so it is quickly converted into the less toxic urea
  • Urea is excreted in the form of urine, small amounts are lost in in sweat

Energy + carbon dioxide + ammonia —–> urea + water

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25
Q

Explain the kidneys in the excretory system

A

Primary excretion organs

Each kidney is about 11cm long

Surrounded by fibrous connective tissue called the capsule

Three layers:
Cortex: outer layer
Medulla: middle layer
Renal pelvis: inner layer

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26
Q

what are nephrons

A

• Nephron: functional unit of the kidney, its where
urine is formed

• Kidneys are composes of a large number of
nephrons

• About 2 million nephrons in each kidney

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27
Q

explain the structure of nephrons

A

Each nephron consist of a renal corpuscle and a renal tube, located in renal pyramids

Renal corpuscle:
- Consists of the glomerulus and glomerular capsule: expanded side of the nephron

Renal tube:
- Leads away from the glomerular capsule
- About 5 cm long
- Begins with a winding section called the proximal
convoluted tubule
- Beyond this each tubule has a straight portion before it
forms the loop of Henle
- Then the tubule becomes coiled again (second coiled
section is called the distal convoluted tube)
- Distal convoluted tube joins a collecting duct that opens up into the renal pelvis (which channels fluid from collecting ducts into the ureter)

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28
Q

Explain the function of nephrons

A

Responsible for removing waste from blood and regulating blood composition:

  • Blood enters the kidney through the renal
    arteries
  • Renal arteries divide into smaller arteries and
    arterioles
  • Each renal corpuscle is supplied with an afferent
    arteriole which forms a knot of capillaries called
    the glomerulus
  • Capillaries unite to form the efferent arteriole
    which passes out of the renal corpuscle
  • After leaving the renal corpuscle the efferent
    arteriole breaks up into a second capillary
    network (peritubular capillaries)
  • These surround the proximal and distal
    convoluted tubules, the loop of Henle and the
    connecting duct
  • Blood drains away from the peritubular
    capillaries and leaves the kidney the renal vein
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29
Q

What are the differences between the afferent and efferent arterioles

A
  1. Afferent arteriole has a wider diameter than the
    efferent arteriole
  2. Afferent arteriole carries blood into the nephron,
    efferent carries blood away
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30
Q

what are the 3 processes involved in urine formation

A

glomerular filtration

selective re-absorption

tubula secretion

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31
Q

what is the process of glomerular filtration

A
  1. Small substances move from the glomerulus into the
    glomerular capsule
  2. Afferent arteriole leading into glomerulus is much
    wider than efferent arteriole leaving it
  3. This increases resistance in blood flow and creates
    high pressure in the capillaries
  4. Capillaries force water and undissolved blood
    components through it’s membrane into the
    glomerular capsule
  5. What’s left behind is residue
    • Blood cells
    • Proteins
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32
Q

what substances move into the glomerular capsule during glomerular filtration

A

water

urea

glucose

amino acids

vitamins

salt

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33
Q

how is filtration enhanced during glomerular filtration

A
  1. increasing pressure and resistance in the
    glomerulus forces substances out
  2. Cells of the glomerular capsule and capillaries are 1
    cell thick
  3. New blood is constantly brought the glomerulus and
    keeps a concentration difference of the substances
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34
Q

what is selective re-absorption

A

Occurs in tubule of nephron and its surrounding peritubular capillaries

Many components of filtrate are useful, so the body uses selective re-absorption to take back what it needs

Must be large surface area achieved by:
- Long length of renal tubule, created by convolution
and lop of Henle
- Large number of nephrons in each kidney

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35
Q

explain the process of selective re-absorption

A

proximal convoluted tubule: glucose, amino acids, water, vitamins and salts are absorbed

loop of henle: ions are re-absorped to adjust pH to 7.3 - 7.4

distal convoluted tubule:
Further reabsorption of water and salt (depending on needs of body)

Water is moved by FACILITATED REABSORPTION (active)

**permeability of membrane in distal convoluted tubule and collecting duct can be changed so more of less water is absorbed

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36
Q

explain what happens during tubular secretion

A

Body removes unwanted waste and regulates pH levels

Substances are secreted back into the tubules:

hydrogen ions

ammonium

creatinine

toxins

drugs

neurotransmitters

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37
Q

explain what coeliac disease is

A

inability to tolerate a protein called gluten

the immune system responds to this by damaging or destroying villi in the small intestine

nutrients cannot be absorbed, and the person becomes malnourished

it is inherited

symptoms include: nausea and vomiting, stomach cramps, fatigue and weakness

treatment: no cure but follow a gluten free diet

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38
Q

whats the chemical equation for cell respiration

A

glucose + oxygen —-> carbon dioxide + water +energy

C6H12O6 + O2 —–> CO2 + H2O + ATP

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39
Q

what are the 2 chemical equations for deamination

A

amino acids + oxygen —-enzymes—-> carbohydrate + ammonia

energy + carbon dioxide + ammonia ——> water + urea

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40
Q

was is the structure and function of the cytoplasm

A

jelly like material

fills space between nucleus and membrane

75 - 90% water

cell organelles suspended in it

regulate osmotic pressure

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41
Q

was is the structure and function of the nucleus

A

largest organelle

oval of sphere shaped

nuclear membrane: double membrane, separates nucleus from cytoplasm

nuclear pore: gaps in the nuclear membrane, lets large molecules enter and leave the nucleus

nucleolus: inside nucleus, contains genetic material in DNA, plays a part in manufacturing proteins

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42
Q

was is the structure and function of the ribosomes

A

very small spherical organelles

site of protein synthesis

either attached to endoplasmic reticulum or free floating in cytoplasm

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43
Q

was is the structure and function of the endoplasmic reticulum

A

pairs of parallel membranes extending from cell membrane to nucleus

channels are for storing or transporting molecules e.g. protein

provides surface for chemical reactions to take place

rough: ribosomes attached
smooth: no ribosomes

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44
Q

was is the structure and function of the Golgi body

A

flattened stacks

modifies and packages proteins

vesicles: small sacks of liquid containing proteins formed at the edges of the golgi body membrane

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45
Q

was is the structure and function of the lysosomes

A

small sphere containing digestive enzymes

remove/break down cell waste

46
Q

what is the structure and function of the mitochondria

A

double membrane (outer and inner folded)

sausage shaped

some chemical reactions of cell respiration occur

provides energy available for cellular activities

47
Q

was is the structure and function of the cell membrane

A

controls/regulates movement of particles in & out of cell

regulates equilibrium in cell

phospholipid bilayer

phosphate head: hydrophilic (water loving), head faces cytoplasm and outside of cell (both mostly water)

glycerol neck connects to:

2 x fatty chain tails: hydrophobic (water hating), faces inward & not in direct contact with water

embedded between the phospholipids are proteins

48
Q

list the different types of proteins embedded in the cell membrane

A

identity protein

receptor protein

carrier protein

channel protein

49
Q

what are the different types of transport across the cell membrane

A

passive: no energy required
active: requires energy

50
Q

explain simple diffusion

A

spreading out of particles from areas of high - low concentration until they’re evenly distributed down a concentration gradient

only occurs in gases and liquids

passive, no energy required

occurs across cell membrane

only lipid soluble substances

51
Q

explain osmosis

A

movement/diffusion of water particles from areas of high to low concentration down a concentration gradient

through AQUAPORINS

water molecules can pass through both phospholipid bilayer and channel proteins.

52
Q

explain the difference between facilitated diffusion and simple diffusion

A

facilitated: passive, with concentration gradient H-L, water soluble, requires assistance
e. g. glucose molecules
simple: passive, with concentration gradient H-L, lipid soluble, straight through membrane
e. g. O2, CO2

53
Q

what are the 2 different types of passive transport

A

diffusion and osmosis

54
Q

describe what active transport is

A

requires energy (ATP: adenosine triphosphate)

against concentration gradient L-H

example of active transport: vesicular transport
e.g. transporting ions

55
Q

explain what vesicular transport is

A

movement of substances across the membrane in membranous sacks called vesicles

active process: energy is needed to form the vesicles

either
endocytosis: taking substances into the cell by vesicular transport. membrane forms around particle until completely enclosed. Vesicle pinches off and is suspended in the cytoplasm. In pinocytosis (liquids) or phagocytosis (solids)

exocytosis: contents of a vesicle inside the cell are passed to the outside. a vesicle migrates to the membrane and fuses with the membrane. contents of the vesicle are the pushed outside of the cell.

56
Q

what are the 4 main types of tissue

A

muscular

epithelium

connective

nervous

57
Q

describe the structure of epithelium tissue

A

cells are arranged in sheets

joined by small amount of intercellular matrix

rest on basement membrane

either:
simple epithelium: 1 layer

connective epithelium: several layers

58
Q

describe the different types of simple epithelium tissue

A

squamous

cuboidal

columnar

ciliated

59
Q

describe compound epithelium tissue

A

several layers of cells

cells become flatter and more scale like closer to the surface

cells lose their living contents in the skin

found in lining of mouth, pharynx and oesophagus

60
Q

what is the function of epithelium tissue

A

lines internal organs and cavities

protects underlying cells from injury, harmful chemicals, bacteria or drying

absorption

secretes waste

sensation

61
Q

describe connective tissue

A

binds parts of the body together

provides support

found in: rib cage, ears, and joints between bones

62
Q

name the different types of connective tissue

A

areolar

adipose

cartilage

bone

63
Q

describe cuboidal epithelium tissue

A

cells are nearly cube shaped

found in the kidney

64
Q

describe columnar epithelium tissue

A

cells are column shaped

long axis at right angle to basement membrane

found in lining of stomach and intestines

65
Q

describe squamous epithelium tissue

A

flattened and scale like

arranged edge to edge

found in lining of the mouth

66
Q

describe ciliated epithelium tissue

A

short, actively waving threads called cilia are attached to cell edges

found in wall of trachea

67
Q

describe areolar connective tissue

A

white and yellow fibres mixed together as well as other non fibrous ground substances

keeps internal organs in place and binds skin to deeper structures

found in:
under skin, binding it to muscle & surrounding various organs

68
Q

describe adipose connective tissue

A

fatty tissue

few fibres and cells are swollen with fat droplets

protects organs close to it

emergency food reserve

found:
under skin, packed around internal organs

69
Q

describe cartilage connective tissue

A

consists of tough matrix

cells are spread far apart; lots of cell matrix between them

cells continuously divide to multiply

each cell produce fresh matrix, spreading them further apart

found:
wall of trachea

70
Q

describe bone connective tissue

A

very firm connective tissue

cells are separated by matrix of organic material

made up of groups of concentric layers of lamellae surrounding the Haversian canal (contains blood vessels and nerves)

in between lamellae lie small cavities, lacunae

lacunae is united with Haversian canal through canaliculi which run through the lamellae

71
Q

describe muscular tissue

A

has the power of contraction

made up of fibres

3 types:
striped/skeletal/voluntary

unstriped/plain/involuntary

cardiac

72
Q

describe striped/skeletal/voluntary muscular tissue

A

builds muscles under control of will

includes most ‘meat’ or ‘flesh’ of an animal

73
Q

describe unstriped/plain/involuntary muscular tissue

A

builds muscle not under control of will

e.g. in the walls of gut and walls of blood vessels

capable of sustaining slow contractions even when separated from nervous system

sensitive to mechanical stimulation e.g. stretching

74
Q

describe cardiac muscular tissue

A

only found in wall of heart

no sarcolemma and have faint cross striations

cells are not properly divides into seperate units, they branch and join with neighbours so a network is formed

75
Q

describe nervous tissue

A

consists of nervous cells or neurones

has supporting tissue called neuroglia

found:
in brain

76
Q

what is the role of an identity protein

A

determine which type of cell it is

77
Q

what is the role of a receptor protein

A

fit with specific molecules to help carry them across the membrane

78
Q

what is the role of a carrier protein

A

assist molecules moving across the membrane easily

79
Q

what is the role of a channel protein

A

open and allow larger molecules to travel across membrane

80
Q

what is meant by ‘breathing’

A

Physical process of inhalation

81
Q

describe the process of inspiration/inhalation

A

External intercostals contract –> ribcage moves up and out

Diaphragm contracts and flattens

Volume of thoracic cavity increases

  • Lungs inflate, increasing volume in the lungs
  • Therefore decreasing pressure
  • Air travels from H-L pressure into the lungs
82
Q

describe the process of expiration/exhalation

A

Internal intercostals contract –> ribcage moves down and in

Diaphragm relaxes and forms a dome shape

Volume of thoracic cavity decreases

  • Lungs deflate, decreasing volume in the lungs
  • Therefore increasing pressure
  • Air travels from HL pressure out of the lungs
83
Q

explain the structure of the lungs

A

Covered by the pleural membrane

The inner layer is attached to the lungs and the outer layer attached to the thoracic cavity

Between the 2 layers is the pleural fluid

It’s attached to the thoracic cavity and reduces friction, protects them as we breathe

84
Q

explain the structure and function of the nasal cavity

A

Divides into 2 sides, each side has 3 shelves

Contains chemo receptors

Cilia hairs filter. Blood capillaries warms. Mucous moistens.

85
Q

what os the function of the larynx

A

Allows for speech, vocal cords vibrate to make sound.

86
Q

explain the structure and function of the trachea

A

Made of c-shaped bands of cartilage that give flexibility and support

Lined with mucous membrane and cells with cilia to trap any solid particles

Cilia beat to move mucous and trapped particles upwards

87
Q

explain the structure and function of the bronchi

A

Pass air from the trachea into each lung.

Contains cartilage rings and a ciliated mucus membrane

Two bronchi branch from the trachea, one left and one right

88
Q

explain the structure and function of the bronchioles

A

Very fine tubes that pass air from bronchi to alveoli.

End in tiny air sacs, the alveoli.

89
Q

explain the structure and function of the alveoli

A

Tiny air sacs at the end of bronchioles

Site of gas exchange

On the outside of an alveolus is a dense network of blood capillaries

One cell layer thick

Cells are moist to increase the rate of diffusion

The huge surface area allows efficient exchange of gasses

90
Q

define gas exchange

A

Process of oxygen diffusing from the alveoli into the blood and carbon dioxide diffusing from the blood into the alveoli in the lungs.

91
Q

explain the process of gas exchange

A

Deoxygenated blood comes from the heart via pulmonary artery. There is a high concentration of C02 in the blood capillaries and a low concentration in the alveolus.

Inspired air in the alveolus contains a high concentration of oxygen, and low in the blood capillaries.

Via the process of diffusion carbon dioxide moves from the capillaries (high concentration) to the alveolus (low concentration).

O2 moves from the Alveolus (high concentration) to the blood capillaries (low concentration).

Oxygenated blood in the capillaries returns to the heart via pulmonary veins.

C02 in the alveolus is expired.

92
Q

why are the lungs well suited to the process of gas exchange

A
  1. Alveoli give the lungs a huge internal surface area, so large amounts of gas can be exchanged more efficiently and quickly
  2. Each alveolus is well supplied kwith blood vessels, so that as much blood as possible is close to air
  3. Alveoli and capillary cell walls are 1 cell thick, so molecules don’t have to travel far when moving in or out of the blood
  4. Lung volume can be changed by movements of respiratory muscles, so air is made to flow in and out of the lungs
93
Q

list 2 disorders of the respiratory system

A

emphysema

asthma

94
Q

explain what emphysema is

A

Caused by long term exposure to irritating particles in the air taken into the lungs

Irritating particles cause damage to alveoli

They lose elasticity and are replaced with fibrous tissue and may break down, reducing surface area for gas exchange

Lungs become constantly inflated and breathing out is a voluntary effort

Symptoms: frequent coughing/wheezing, cough produces mucous, tightness in chest, shortness in breath especially in physical activity

Treatment: cannot be cured, once lung damage begins progression of disease cannot be stopped

95
Q

explain what asthma is

A

Difficulty breathing caused by narrowing of airways

Occurs due to: smooth muscles contracting: blocking airways, mucous filling airway, narrowing the tube

Triggers include: respiratory infections, cigarette smoke, allergens e.g. dust, pollen and animals

During asthma attack muscles surrounding the bronchi spasm and cause narrowing of air passages, therefore difficult breathing

Irritation of membrane lining passage secretes excess mucous, restricting movement of air

Gas exchange is reduced and blood doesn’t carry normal amount of oxygen

Symptoms: difficulty breathing, severe chest pain, coughing and wheezing

Treatment: bronchodilator, inhaler, anti-inflammatory medication

96
Q

explain the carrying of oxygen gas

A

3% is dissolved in blood (plasma)
97& dissolved in oxyhaemoglobin

  • At the alveoli oxygen enters into RBCs and attatches to
    the ‘haem’ part of the haemoglobin molecule
  • At the cells oxygen breaks off the haemoglobin
    molecule and enters fluid outside of the cell, the moves
    into the cell
97
Q

explain the carrying of carbon dioxide gas

A

8% dissolved in blood (plasma)
22% dissolved in the ‘globin’ part of haemoglobin in RBCs

  • At the cells 22% of CO2 attached to the globin part of
    the haemoglobin molecule
  • At the alveoli CO2 breaks away and moves into the
    alveoli to be exhaled

70% converted into bicarbonate ions
- CO2 diffuses out of cell and react with water around
the cell to form carbonic acid
- Carbonic acid ionises to produce H+ ions and HCO3-
ions
- At the alveoli this reaction reverses

98
Q

what is the chemical equation for the conversion of carbon dioxide gas into bicarbonate ions

A

CO2 + H2O (arrows) H2CO3 (arrows) H+ + HCO-3

99
Q

what are the functions of the circulatory system

A

Body’s main transport system

Link between cellular requirement inside the body and outside environment that supplies these requirements

Blood is the transport link between cells and all the body systems

Some important functions of blood are:
- Transporting oxygen, nutrients and hormones to cells
- Transporting carbon dioxide and waste away from cells
- Maintaining pH and water & ion concentration of body
fluids
- Distribution of heat and maintaining body temperature

100
Q

explain the structure of the heart

A

Pump that pushes blood around the body

Located between the lungs in the mediastinum & behind and slightly to the left of the sternum

Conical shape approximately 12 cm long, 9 cm at its widest and 6 cm wide

It is enclosed in the pericardium (its membrane)

Wall of heart is made of cardiac muscle

Right side: collects deoxygenated blood from the body and pumps it to the lungs

Left side: collects oxygenate blood from the lungs and pumps it around the body

Each side is separated into 2 chambers: atria & ventricles

101
Q

what is the purpose of the pericardium

A
  • Holds heart in place
  • Allows for movement
  • Prevents overstretching
102
Q

explain the structure, function and percentage composition of red blood cells in blood

A

composition in blood: 45%

Biconcave disc shape

No nuclei: more room to carry haemoglobin that binds with oxygen

Flexible: fit through capillaries

Carry oxygen, bound to the protein haemoglobin

Live for approximately 120 days

Produced in red bone marrow

destroyed in liver and spleen

103
Q

explain the structure, function and percentage composition of white blood cells in blood

A

composition: <1%

Larger than RBC but fewer

2 types:
- Granulocytes: granular cytoplasm and spherical
nucleus
- Monocytes and lymphocytes: agranular cytoplasm and
spherical nucleus

Able to change shape

Removes dead/injured cells and invading

104
Q

explain the structure, function and percentage composition of plasma in blood

A

composition: 55%

91% water

The rest is dissolved substance e.g. ions, gases, hormones

Pale yellow colour

Liquid part of the blood

105
Q

explain the structure, function and percentage composition of platelets in blood

A

composition: <1%

small cell fragments

no nucleus

formed in red bone marrow

last for 7 days

jagged edges

106
Q

what are the functions of blood clotting

A

Minimise blood loss

prevent entry of microorganisms

107
Q

what are the 3 stages of blood clotting

A

vasoconstriction

platelet plug formation

coagulation

108
Q

explain the stage of vasoconstriction in the process of blood clotting

A

Blood Vessel constricts reducing blood flow to that area.

109
Q

explain the stage of platelet plug formation in the process of blood clotting

A

Walls of blood vessel becomes rough

Platelets in plasma become stuck to the rough walls

More platelets come to the site and stick to each other

Platelets release chemicals which prolong vasoconstriction

110
Q

explain the stage of coagulation in the process of blood clotting

A

Chemicals form thread-like proteins called Fibrin

Fibrin threads form a mesh network around the plug

Fibrin seals wound from outside the blood vessel wall and traps RBCs

This build up causes a clot

Network of threads contracts and pulls the edges of the damaged vessels together

Fluid gets squeezed out of the cut and dries, causing a scab

Human bio (16 decks)

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