organisation in animals 1 Flashcards

the human digestive system, levels of organisation, bile, heart, blood vessels, blood

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1
Q

why is the heart considered to be an organ

A

organ - group of tissues that work together to perform a specific function
the function of the heart is to pump blood throughout your body
the heart is mainly made up of a type of muscle tissue called cardiac muscle

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2
Q

what tissues make up the stomach and what is the function of each tissue type

A

stomach - made of mucosa - inner lining on stomach and is made of glands that make mucus, hydrochloric acid and enzymes
mucosa has ridges - rugae - when the stomach is empty (flattens as stomach fills)

surrounding mucosa - submucosa - connective tissue that contains larger blood and lymph vessels, nerve ends & fibres

covering submucosa - muscularis propria that’s the main stomach muscle and is made of 2 fatty layers

covering outside of stomach - serosa that is called the visceral peritoneum

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3
Q

the human digestive system (10)

A

mouth - teeth break down food and mix it with enzymes in saliva

oesophagus - thin tube that connects mouth to stomach

stomach - muscular bag which mixes food and drink with acid

small intestine - carbohydrates, proteins and lipids digest and nutrients are absorbed into blood

large intestine - non broken down foods pass here and water is absorbed into blood

rectum - undigested food passes here where it’s spread as faeces

anus - opening at the end of the digestive system where faeces leaves the body

liver - releases a chemical called bile into intestines which breaks down lipids

pancreas - releases enzymes into the intestines which breaks down carbohydrates, proteins and lipids in food

gallbladder - stores bile and releases it into the small intestine

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4
Q

levels of organisation (8)

A

cells - smallest unit of life that shows all 7 characteristics of living things

tissues - groups of similar cells linked together doing the same job

organs - groups of tissues working together to perform a function

organ system - organs working together

organism - groups of systems working together to make one independent living thing

population - groups of individual organisms of the same species

community - different species and the relationships between them

biosphere - relationship between all living and non-living parts of the planet

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5
Q

point of digestion

A

large food molecules (carbohydrates, proteins, fats) are too big to be absorbed.

physical and chemical digestion break down these large molecules into smaller ones

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6
Q

what is bile

A

produced in liver and stored in gallbladder

2 main roles:
- neutralises stomach acid as it enters the small intestine to provide correct pH for the small intestine enzymes
- emulsifies (breaks up) fat into smaller fat droplets to provide a larger surface area for lipase enzymes to work on

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7
Q

4 chambers of the heart

A

two atria at the top and two ventricles at the bottom

upper right and left atria receive incoming blood
the lower, more muscular right and left chambers squeeze and pump blood out of the heart

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8
Q

right side of the heart

A

pulmonary circulation

  • deoxygenated blood from body
  • enters heart through vena cava
  • drains into right atrium
  • flows through tricuspid valve to right ventricle
  • blood leaves through pulmonary valve into pulmonary artery
  • goes to lungs
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9
Q

left side of heart

A

systemic circulation

  • pulmonary vein carries oxygenated blood from lungs
  • blood goes to the left atrium
  • through mitral valve blood flows from left atrium to left ventricle
  • through the aortic valve into the aorta the blood then leaves
  • flows to rest of body
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10
Q

blood flow in terms of veins and arteries

A

blood is pumped TOWARDS the heart in veins and AWAY from the heart in Arteries

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11
Q

why is the left ventricle wall more thick than the right ventricle wall

A

the left ventricle has to pump blood all around the body at a high pressure

the right ventricle pumps blood at a lower pressure to the lungs (closer to the heart)

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12
Q

what is self-regulating

A

when something doesn’t require messages from anywhere to keep it going – heart

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13
Q

pacemaker cells

A

the heart has pacemaker cells in the right atrium which create electricity
these signals cause the muscular walls of the ventricles to contract (to beat)

if someone’s heart doesn’t beat as it should, they can be fitted with an artificial pacemaker

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14
Q

describe and explain an artery

A
  • circular shape
  • two layers
  • small lumen (inner hole)
  • thickk layer of muscles and elastic fibres
  • outer thick-ish wall

–>needs thick, muscular, elastic walls to carry blood under high pressure
–> small lumen expands when blood forces through

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15
Q

describe and explain a vein

A
  • triangular shape
  • two layers
  • large lumen (inner hole)
  • thin layer of muscle and elastic fibres
  • fairly thin outer wall

–> needs thinner, less muscular walls than arteries as they carry low pressure blood
–> they have a bigger lumen than arteries
–> they have valves to protect backflow of blood

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16
Q

describe and explain a capillary

A
  • small circular shape
  • one layer
  • very small lumen
  • wall made of single layer cells

–> has very thin walls to provide a short diffusion pathway for exchange of substances
–> very small lumen to allow one red blood cell through at a time and to increase contact between blood cells & capillary walls

17
Q

what is blood made of

A

red blood cells
white blood cells + platelets
plasma - water, ions, proteins, nutrients, waste, gases

18
Q

describe red blood cells in the blood

A
  • picks up and carries oxygen
  • 45% of blood
  • biconcave discs, no nuclei, packed with haemoglobin
19
Q

describe white blood cells in the blood

A
  • larger cell within nuclei
  • <1% of blood
  • part of the body’s defense system against microorganisms
20
Q

describe plasma in the blood

A
  • yellow liquid
  • carries cells, platelets, dissolved substances
  • 55% of blood
21
Q

describe platelets in the blood

A
  • important in blood clotting
  • small fragments of cells, no nuclei
  • <1%