Physiology

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Physiology Transport
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Contents

• Transport Systems
• Control of Breathing and heartbeat
• Energy and Exercise
• Transport of Substances in Plants

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Human Circulatory System

• Pumps materials as a fluid quickly around body
• Double circulatory system

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Blood entering via vessel Organ Blood leaving via vessel
Carotid artery Head Jugular Vein
Hepatic artery Liver Hepatic vein
Renal artery Kidneys Renal vein
Superior and inferior vena cavaPulmonary vein Heart Pulmonary artery Aorta
 
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How the Blood is Transported
Arteries carry blood away from the heart at high
pressure in thick walled lumen
Capillaries have thin walls to allow glucose and
oxygen to diffuse through
Veins carry low pressure blood back to the heart.
Veins have thinner walls and valves to prevent
backflow of blood
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Blood Vessels
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Arteries

• Carry blood at high pressure
• Outermost layer is composed of connective tissue
• Media smooth muscle cells and elastic tissue
• Intima in direct contact with flow of blood
• Lumen cavity in which blood flows

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Capillaries

• Most exchange of nutrients and gases takes place
  here
• Small diameter, large surface area for diffusion
• Lungs ? carbon dioxide is exchanged for oxygen
• Tissues ? O2, CO2, nutrients and wastes are
  exchanged
• Kidneys ? wastes are released to be eliminated
  from body
• Intestine ? nutrients are picked up, wastes are
  released

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Parts of the Blood
 
Substance Where Reason
Oxygen Red blood cells Transported from lungs to all cells for respiration
Carbon dioxide Plasma Transported from all cells to lungs for excretion
Nutrients (e.g. glucose, amino acids, vitamins, lipids, nucleotides) Plasma Transported from small intestine to liver and from liver to all cells
Waste products (e.g. urea, lactic acid) Plasma Transported from cells to liver and from liver to kidneys for excretion
Hormones Plasma Transported from glands to target organs
Proteins Plasma Amino acid reserve
Blood clotting factors Plasma At least 13 different substances (mainly proteins) required to make blood clot.
Antigens and antibodies Plasma Part of immune system
Water Plasma Transported from large intestine and cells to kidneys for excretion.
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Parts of the Blood
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Circulatory System
Oxygenated blood enters through the pulmonary
veins into the left atrium
Deoxygenated blood enters through the vena cava
into the right atrium
Its then pumped through a valve into the right
ventricle chamber
Its then pumped through a valve into the left
ventricle
And then up through the pulmonary valve into the
pulmonary artery towards the lungs
And then through the aortic valve and out of the
aorta to the rest of the body
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Cardiac Cycle

• Atrial Systole
• Sino-atrial node contracts and transmits
  electrical impulses throughout atria. These
  contract and pump blood into ventricles
• Ventricular Systole
• Electrical impulse passes to ventricles via
  atrioventricular node, bundle of His and Purkinje
  fibres. Fibres do not contract, but pass impulse
  to base of ventricles. Ventricle contract shortly
  after atria, squeezing blood upwards into
  arteries
• Diastole
• Atria and ventricles relax
• ? atria filll with blood

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Exercise and Heart Rate

• Cardiac output blood flow at a given time
• Cardiac output heart rate x stroke volume
• At rest approx. 5500
• Exercise approx. 22000
• Benefits of high output during exercise
• - oxygen glucose reach muscles faster
• - Lactate, heat and CO2 removed from muscles
  faster

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Cardiovascular Centre

• Part of human brain responsible for regulation of
  heart beat rate
• Alters heart rate during exercise and body trauma
• Increases stroke volume of heart
• Sufficient amount of blood then reaches tissue
• Adrenaline and other hormones affect the
  cardiovascular centre and cause it to increase
  the rate of impulses which in turn increases the
  heart beat rate

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Breathing

• Ventilation rate volume of air ventilating the
  lungs / minute
• Ventilation rate breathing rate x tidal volume
• At rest approx. 6000
• Exercise approx. 18000
• Benefits of high output during exercise
• - oxygen diffuses from air to blood faster
• - CO2 diffuses from blood to air faster

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Water Transport in Plants

• Plants require water for growth, temperature
  regulation and to hold themselves up
• Transpiration system
• Water absorbed into roots through root hair cells
• Water carried to leaves through xylem vessels
• Water evaporates from underside of leaves
• Water escapes through holes called stomata
• As water evaporates, more is sucked up xylem
• Stomata open and close to control water loss
• Open O2 and CO2 enter and exit
• Closed Reduce water loss

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Water Transport in Plants

• Water is absorbed in plants by young roots and in
  the dermal cells by osmosis
• Cell sap of the epidermal cells has higher
  concentration than water in the soil
• Root hairs significantly increase water
  absorption
• Root hairs increase the root surface area and
  catchment space for water uptake
• epidermal cells do not have a cuticle ? water
  uptake is fast

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Structures
Stem Structure Root Structure
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Xylem and Phloem Vessels
Xylem Phloem
Made of Dead cells Living cells
Cell wall thickness Thick Thin
Cell wall material Lignin (rigid) Cellulose
Permeability Impermeable Permeable
Cytoplasm? None Cytoplasm lining
Transports Water minerals Food
Carried to Leaves Growing parts storage organs
Direction of flow Upwards Up and down
Tissue also has Fibres Companion cells

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Water Provides Support

• Green plants rely on cell turgor to hold
  themselves up
• Cell walls become turgid with water
• In woody plants, they do not need cell turgor,
  but instead rely on the support of the strong,
  impermeable xylem vessels

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Movement Through Roots
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Movement Through Leaves
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Mineral Ion Transport in Plants

• Plant mineral nutrients are in solution in soil
  water
• The root dermal cells absorb the mineral
  nutrients by diffusion and active transport
• The root dermal cells are rich in the ATP
  producing mitochondria
• The mineral nutrients are actively pumped into
  the xylem
• The mineral nutrients are transported throughout
  the plant in the xylem

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Food Transport in Plants

• Food transport is an active process because ATP
  is needed. This can move up or down the stem
• Food is transported in the sieve tube elements of
  the phloem
• Phloem sap is a solution of sugar
• Sugar made in the leaves by photosynthesis is
  transported to the growing points. Excess is
  often sent to the roots for storage
• At the start of the growing season the food is
  transported from the storage regions to the
  growing points

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CO2 Transport in Plants

• Carbon dioxide gas enters the leaves by diffusion
  through the stomata
• Carbon dioxide diffuses to the photosynthetic
  cells through the leafs air spaces
• Carbon dioxide diffuses into the intercellular
  air spaces from respiring plant tissue
• This carbon dioxide gas diffuses through the air
  spaces to photosynthetic tissue
• Diffusion in air is much faster than in water

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Summary

• Double circulatory system in humans
• Red white blood cells, platelets plasma make
  up blood
• Blood is carried through veins, capillaries and
  arteries
• Heartbeat is controlled by the cardiovascular
  centre
• Exercise affects the cardiovascular centre which
  in turn affects the heartbeat rate
• Substances are transported in plants. These
  include, water, CO2, food and mineral ions