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Transport Systems

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Title: Transport Systems


1
Chapter 7
  • Transport Systems

2
Transport
  • Small, simple organisms living in water can
    obtain nutrients and eliminate wastes through
    diffusion.
  • What about larger, more complex organisms?

3
Plant Transport Systems
  • The first land plants evolved from green algae
    about 430 million years ago.
  • Life on land presented challenges for plants
    loss of moisture to the air, ability to get
    nutrients from soil and air, ways to eliminate
    wastes.
  • Plants have specialized structures to cope with
    the challenges.

4
Plant Terminology
  • Vascular Plants are plants with specialized
    tissues for water and nutrient transport.
  • Nonvascular Plants are plants without these
    tissues and must live in damp places.
  • Lignin is a hard material embedded in the
    cellulose matrix of cell walls to help support
    large vascular plants.

5
Plant Terminology Continued
  • Xylem is hollow-tube shaped cells that carry
    water and minerals up from the roots.
  • Phloem are elongated cells arranged into tubes
    filled with streaming cytoplasm that moves
    organic materials throughout the plants.

6
Water Transport
  • Xylem is made up of two types of water conducting
    cells.
  • Tracheids which have pitted walls through which
    water moves from cell to cell.
  • Vessel Elements are wide thin-walled cells that
    are open on the ends, so water flows freely
    through these.

7
  • Water loss is especially challenging, plants lose
    water through their stomates, which are open to
    facilitate gas exchange for photosynthesis.
  • A red maple growing in a humid climate loses as
    much as 2,000L per day (1000 2L coke bottles).
  • Plants must constantly replace this lost water.
  • How is the water moved from the roots to the very
    tip of the plant?

8
  • The current hypothesis is the cohesion-tension
    hypothesis.
  • Root pressure, cohesion of the water molecules,
    and adhesion of the water to other charged
    molecules (which are found in the walls of the
    tubular cells) and the transpiration of the water
    leaving the plant essentially tug the water up.

9
Plant Nutrient Transport
  • In plants, nutrients travel through phloem cells
    that are joined end-to-end. Tiny pores in the
    walls at the ends of the phloem cells allow the
    contents of cells to mix.
  • Tiny strainer-like cells called sieve tubes are
    located at the tips of the cells.

10
  • Sugars and Amino Acids move through the phloem
    cells from the leaves to the other parts of the
    plants.
  • The best explanation is that the materials move
    from the source to the sink or from areas of
    high pressure to areas of low pressure.

11
Transport Systems in Animals
12
Circulatory Systems
  • Like plants, animals must also have a way to
    exchange materials between cells and the
    environment.
  • Unicellular organisms living in water
    environments can rely on diffusion and active
    transport.
  • Larger organisms must have specialized systems.

13
  • The size of an organism and its activity level
    determine the complexity of the transport system.
  • In arthropods, (insects, crabs, etc.) there is an
    open circulatory system. There is no separation
    between the blood and other fluids. These
    organisms may or may not have some type of heart
    to help pump the blood throughout their body
    cavity.

14
Open Circulatory System
  • In an open system, the blood is in the body
    cavity or hemocoel and is pumped by the hearts.

15
Closed Circulatory System
  • In a closed system, blood is contained in
    vessels.
  • These vessels branch into smaller and smaller
    vessels.
  • The heart pumps blood through the system.

16
Circulation in Vertebrates
  • Humans and other vertebrates have closed
    circulatory systems also called cardiovascular
    systems.
  • The components are
  • The heart
  • Blood Vessels
  • Blood

17
Circulatory System
  • This example shows some of the major vessels of
    the human circulatory system.

18
Blood Vessels
  • There are 3 types of blood vessels.
  • Arteries carry blood AWAY from the heart. In all
    but one artery, this is oxygenated blood.
  • Veins carry blood TO the heart. In all but one,
    this is de-oxygenated blood.
  • Capillaries are the microscopic vessels that form
    a network in the tissues. These are where gas
    exchange occurs (remember the respiratory system)

19
Capillary
  • Capillaries make the transition from arteries to
    veins.

20
The Heart
  • Mammals have a 4-chambered heart and most
    amphibians and reptiles have a 3-chambered heart.
  • The heart pumps to move blood throughout the
    body.

21
The Human Heart
22
The Cardiac Cycle
  • The cardiac cycle is the series of muscle
    contractions and relaxations. This is the
    heartbeat that is heard with a stethoscope.
  • Contraction is called systole and the relaxation
    period is called diastole.
  • The chambers contract and relax together.

23
Blood Flow through the Heart
24
Heartbeat
  • Each heart beat starts with the pacemaker. These
    are cells located in the inner wall of the right
    atrium.
  • This pacemaker (sinoatrial node) creates
    electrical impulses that cause the cardiac muscle
    to contract.

25
  • The impulse spreads to the atrioventricular node
    in the left atrium and produces a unified
    contraction of the atria.
  • The signal is conducted through fibers in the
    ventricles called the bundle of HIS and the
    Purkinje fibers which generate a strong
    ventricular contraction.

26
Composition of Blood
  • Blood contains cells, fluids, and dissolved
    substances.
  • The main components are
  • Erythrocytes red blood cells
  • Leukocytes white blood cells
  • Plasma fluid portion of blood
  • Platelets small cell fragments

27
Erythrocytes
  • Red blood cells contain the oxygen-transporting
    protein called hemoglobin.
  • It gives these cells their characteristic red
    color.
  • They live about 120 days.

28
Erythroctyes
  • New cells are made in the marrow of the long
    bones.
  • A hormone in the kidneys regulates the
    production.
  • Human RBCs do not have a nucleus.

29
Leukocytes
  • White blood cells are the bodys second line of
    defense after the skin and mucous membranes.
  • There are 5 types of WBCs, each with its own role
    in defending the body.

30
Neutrophils
  • Neutrophils ingest bacteria at a wound site.
  • Most abundant white blood cell.

31
Eosinophils
  • Eosinophils also destroy bacteria. They are
    cytotoxic.

32
Basophils
  • Basophils play a role in ridding the body of
    foreign matter by ingesting the substances.

33
Monocytes
  • Monocytes absorb bacteria with the body at the
    site of an infection.
  • Mature into macrophages.
  • Increase greatly in response to infection.

34
Lymphocytes
  • Two types, called B-Cells and T-Cells.
  • When stimulated, B-cells become plasma cells.
  • T-cells regulate the immune response of the
    leukocytes reduced by AIDS/HIV

35
Plasma
  • The fluid portion of the blood.
  • Contains
  • Water,
  • Proteins
  • Dissolved ions
  • Amino acids and sugars
  • Carries CO2, wastes, digested food, hormones,

36
Platelets
  • Platelets are irregularly-shaped, colorless
    bodies that form clots to stop bleeding.
  • Platelets gather at the wound and attempt to
    block the blood flow.

37
Blood Pressure
  • Blood vessels have different amounts of muscle
    and elasticity depending on the function of the
    vessel.
  • Arteries are very muscular due to the pressure of
    the blood when the heart contracts. The artery is
    very elastic so that it can expand and contract
    as blood flows.
  • The contraction of the artery muscles help push
    blood through the system.

38
  • Veins are not as muscular or elastic because the
    pressure is not as great.
  • Veins have valves to prevent the backflow of
    blood.
  • Gravity and skeletal muscle contraction helps
    direct blood through the veins (in addition to
    the blood flow from behind).

39
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40
Blood Pressure
  • A healthy blood pressure is maintained by
    hormones, and the nervous, excretory, and
    circulatory systems.
  • About 20 of the US adult population has high
    blood pressure (hypertension).
  • This forces the heart work harder and can damage
    vessels, causes strokes and contributes to
    artherosclerosis.

41
Muscle Contraction
  • Heart muscle is called cardiac muscle. It is
    involuntary (contacts without your control).
  • Muscle is made of two proteins actin and
    myosin.
  • Actin filaments are anchored at a z-line. Myosin
    filaments contact the actin with crossbridges.
    During contraction the crossbridges walk along
    the actin toward the z-lines by a release-attach
    motion, which in turn causes contraction.

42
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43
Muscle Contraction Animations
  • http//bio.winona.msus.edu/berg/ANIMTNS/SlidFila.h
    tm
  • http//3dotstudio.com/zz.html
  • http//www.sci.sdsu.edu/movies/actin_myosin_gif.ht
    ml
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