Chapters 22-23 Gas Exchange and Circulation - PowerPoint PPT Presentation

1 / 24
About This Presentation
Title:

Chapters 22-23 Gas Exchange and Circulation

Description:

Chapters 22-23 Gas Exchange and Circulation Gas exchange Three phases of gas exchange; 1. breathing 2. transport of gases by circulatory system - O2 in, CO2 out 3 ... – PowerPoint PPT presentation

Number of Views:141
Avg rating:3.0/5.0
Slides: 25
Provided by: ChrisH345
Category:

less

Transcript and Presenter's Notes

Title: Chapters 22-23 Gas Exchange and Circulation


1
  • Chapters 22-23 Gas Exchange and Circulation

2
Gas exchange
  • Three phases of gas exchange
  • 1. breathing
  • 2. transport of gases by circulatory system - O2
    in, CO2 out
  • 3. cells take up O2 and get rid of CO2
  • What is the destination of the oxygen?
  • The mitochondria. All cells need oxygen for
    cellular respiration

3
Respiratory system form and function
  • Since gas exchange occurs by diffusion, the
    surface area of the respiratory system must be
    extensive.
  • Examples-
  • 1. skin breathers earthworms
  • 2. branched respiratory surfaces tracheal
    systems, gills, and lungs

4
Similarities in structure and function?
5
Adaptations and environments
  • Aquatic water has low O2 content.
  • How is gas exchange accomplished?
  • Countercurrent exchange-blood flows in the
    opposite direction of the water flow.
  • Why dont you see terrestrial animals with gills?
  • They would dry out.
  • Solution?
  • Internal respiratory system.

6
(No Transcript)
7
Mammalian respiratory systems
  • Larynx (upper part of respiratory tract)
  • Vocal cords (sound production)
  • Trachea (windpipe)
  • Bronchi (tube to lungs)
  • Bronchioles
  • Alveoli (air sacs)
  • Diaphragm (breathing muscle)

8
Structure and function
  • How does the structure of the alveoli match their
    function?
  • Clusters of these air sacs have an enormous
    surface area 50 times that of the skin.
  • Lined with thin epithelial cells lined with
    capillaries allowing for diffusion of both O2 and
    CO2 for efficient transport.

9
Transport of gases in the human body
  • Oxygen and carbon dioxide diffuse down their
    partial pressure gradients.
  • What is the transporting vehicle?
  • Most animals use hemoglobin to transport both O2
    and CO2.
  • How does a human fetus breath?
  • Capillaries in the umbilical cord exchange gases
    with the mothers bloodstream.

10
Circulation system evolution, I
  • Gastrovascular cavity (cnidarians, flatworms)
  • Open circulatory - Hemolymph (blood
    interstitial fluid). Sinuses (spaces surrounding
    organs)
  • Closed circulatory - Blood confined to vessels
  • Cardiovascular system - heart (atria/ventricles),
    blood vessels (arteries, arterioles,
    capillary beds, venules, veins), blood
    (circulatory fluid)

11
Open vs closed systems
12
Circulation system evolution, II
  • Fish 2-chambered heart single circuit of blood
    flow
  • Amphibians 3-chambered heart 2 circuits of
    blood flow- pulmocutaneous (lungs and skin)
    systemic (some mixing)
  • Mammals 4-chambered heart double circulation
    complete separation between oxygen-rich and
    oxygen poor blood

13
Circulatory system examples
14
Single vs double circulation
  • What is the difference between single and double
    circulation?
  • In fish, the blood travels to the gill
    capillaries to systemic capillaries before
    returning to the heart. In land vertebrates,
    blood is returned to the heart and then pumped a
    second time between the pulmonary and systemic
    circuits.

15
Double circulation
  • From right ventricle to lungs via pulmonary
    arteries
  • Capillary beds in lungs to left atrium via
    pulmonary veins
  • Left atrium to left ventricle to aorta
  • Aorta to coronary arteries then systemic
    circulation
  • Back to heart via two venae cavae (superior and
    inferior) right atrium

16
Blood flow through the human heart
17
The mammalian heart
  • Cardiac cycle sequence of filling and pumping
  • Systole- contraction
  • Diastole- relaxation
  • Cardiac output volume of blood per minute
  • Heart rate- number of beats per minute
  • Stroke volume- amount of blood pumped with each
    contraction
  • Pulse rhythmic stretching of arteries by heart
    contraction

18
The heartbeat
  • Sinoatrial (SA) node (pacemaker) sets rate
    and timing of cardiac contraction by generating
    electrical signals
  • Atrioventricular (AV) node relay point (0.1
    second delay) spreading impulse to walls of
    ventricles
  • Electrocardiogram (ECG or EKG)

19
Cardiovascular disease
  • Cardiovascular disease (gt50 of all deaths)
  • Heart attack- death of cardiac tissue due to
    coronary blockage
  • Stroke- death of nervous tissue in brain due to
    arterial blockage
  • Atherosclerosis arterial plaques deposits
  • Arteriosclerosis plaque hardening by calcium
    deposits
  • Hypertension high blood pressure
  • Hypercholesterolemia LDL, HDL

20
Structure and function of blood vessels
  • How does the structure of a capillary relate to
    its function?
  • The small diameter and thin walls of the
    capillary facilitate the exchange of substances
    between the blood and interstitial fluid.

21
Blood vessel structural differences
  • Capillaries
  • endothelium basement membrane
  • Arteries
  • thick connective tissue thick smooth muscle
    endothelium basement membrane
  • Veins
  • thin connective tissue thin smooth muscle
    endothelium basement membrane

22
BLOOD
  • Plasma liquid matrix of blood in which cells are
    suspended (90 water)
  • Erythrocytes (RBCs) transport O2 via hemoglobin
  • Leukocytes (WBCs) defense and immunity
  • Platelets clotting
  • Stem cells pluripotent cells in the red marrow
    of bones
  • Blood clotting fibrinogen (inactive)/ fibrin
    (active) hemophilia thrombus (clot)

23
(No Transcript)
24
Stem cells
  • http//www.hhmi.org/biointeractive/stemcells/zebra
    fish_regen.html
Write a Comment
User Comments (0)
About PowerShow.com