Transcript lecture 14 ppt

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Thought Question:
What are the functions of your circulatory system?
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Lecture 14 Outline (Ch. 42)
I.
Circulatory Systems
II.
Human Heart
III. Blood
IV. Blood Vessels
V.
Cardiovascular disorders
VI. Lymph
VII. Gas Exchange (Bulk Flow & Diffusion)
VIII. Gas Transport
IX. Breathing
X.
Respiratory problems & Smoking
XI. Lecture Concepts
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Circulation Overview
Circulation carries energy,
dissolved gasses, wastes
•
•
Connects individual cells in distant
parts of body
Requirements
– Blood – fluid for transport
– Blood vessels – channels for
transport
– Heart – pump for circulation
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Circulation Overview
Circulatory systems are open or closed
•
•
Open- bathes organs in a hemocoel
Closed- direct vessel connections to organs
Heart
Hemolymph in sinuses
surrounding organs
Pores
Heart
Blood
Interstitial
fluid
Small branch vessels
In each organ
Dorsal vessel
(main heart)
Tubular heart
(a) An open circulatory system
Auxiliary hearts
Ventral vessels
(b) A closed circulatory system
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Circulation Overview
Vertebrates have a closed circulatory system
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•
More efficient
– Blood is 5 – 10% of body volume
– Blood flow is more rapid
– Blood pressure is higher
Multifunctional
– Transport dissolved gasses
– Distribute nutrients
– Transport waste
– Distribute hormones
– Thermoregulation
– Circulate immunodefenses
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The Vertebrate Heart
•
Set of
muscular
chambers
•
Atria collect
blood
Ventricles
send blood
through body
•
•
The heart
has
evolved
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Heart
4-chambered heart: A closer look
•
2 pumps
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•
Right: deoxygenated blood
Left: oxygenated blood
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Heart
•
Right atrium receives deO2 blood from veins
– Superior vena cava
– Inferior vena cava
Right ventricle pumps
deO2 blood to lungs
through pulmonary
arteries
Pumps into right ventricle
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Heart
•
Oxygenated blood returns to left atrium from lungs via
pulmonary veins
Oxygenated blood
pumped to body
through aorta
Pumps into left ventricle
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Heart
Cardiac muscle contracts
•
Present only in the heart
Cells linked by
intercalated discs
Prevents strong contractions
from tearing muscle
Allows rapid spread of
electrical signal for
simultaneous
regional
contraction
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Heart
The Cardiac Cycle
•
Coordinated contractions of atria & ventricles
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Heart
The Cardiac Cycle & Blood Pressure
•
•
Systolic
– Ventricular contractions
(higher pressure)
Diastolic
– Period between
contractions (lower
pressure)
Normal blood pressure ~120/80
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Heart
Keeping blood moving
•
•
•
Heart valves maintain oneway flow
Atrioventricular valves
– Between atria &
ventricles
Semilunar valves
– Between ventricles &
arteries
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Heart
Keeping blood moving
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Pacemaker cells initiate and
coordinate contractions
Sinoatrial (SA) node
– Primary pacemaker
– Stimulates atrial
contractions
Atrioventricular (AV) node
– Slows impulse received
from SA node
– Delays ventricular
contraction until after
atrial contractions have
filled them with blood 15
Blood
Plasma
•
•
Primarily water
Dissolved proteins and electrolytes
Blood
•
•
Plasma fluid
Cells
– Red blood cells – transport
– White blood cells – defense
– Platelets – clotting
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Blood
Red blood cells: Erythrocytes
•
•
•
Most abundant blood cells (over 99%)
Transport O2 and CO2
Iron-based hemoglobin protein binds to O2 and
transports from areas of high concentration to
low concentration
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Blood
Erythrocytes are short-lived
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Formed in bone marrow
Lack nuclei (cannot divide or make proteins)
Dead cells are removed by liver and spleen
– Iron is recycled, although some is excreted
Number of erythrocytes
maintained by negative
feedback
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Blood
White blood cells: leukocytes
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•
Less than 1% of blood cells
Disease defense
–
–
–
–
–
Consume foreign
particles
(macrophages)
Produce antibodies
(lymphocytes)
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Blood
Platelets
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Cellular fragments
aid blood clotting
Ruptured cells and
platelets work
together to produce
substances that plug
damaged vessels
Scabs are platelets
embedded in web of
fibrin proteins
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Blood is carried in
vessels
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Artery
Vein
SEM
Valve
100 µm
Basal lamina
Endothelium
Smooth
muscle
Connective
tissue
Endothelium
Smooth
muscle
Capillary
Connective
tissue
Artery
Vein
Capillary
15 µm
Red blood cell
Venule
LM
Arteriole
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Blood Vessels
Arteries
Arterioles
Arteries
• Carry blood away from heart
• Thick-walled:
Heart
Capillaries
• Smooth muscle/elastic fibers
• Withstand high pressure
Veins
Venules
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Blood Vessels
Arteries
Arterioles
Arterioles
• Control distribution of blood flow
• Smooth muscle expands / contracts
• Under hormone / NS control
Capillaries
Heart
Veins
Venules
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Blood Vessels
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•
•
•
Arterioles
Contract walls: redirects blood to heart and muscles
when needed (stress, exercise, cold)
Relax walls: brings more blood to skin capillaries to
dissipate excess heat
Precapillary sphincters control blood flow to
capillaries
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Blood Vessels
Arteries
Arterioles
Capillaries
• Nutrients/waste exchanged with cells:
• Vessel wall one-cell thick
• Blood flow very slow
Capillaries
Heart
• Materials exit/enter via diffusion
Veins
Venules
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Blood Vessels
Capillaries connect & exchange
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•
Tiny vessels
Connect arterioles and venules
•
Interstitial fluid leaks from plasma in
capillaries and provides cells with means of
exchange
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Blood Vessels
Arteries
Arterioles
Venules & Veins
• Carry blood towards the heart
Heart
Capillaries
• Thin-walled; large diameter
• One-way to prevent backflow
Veins
Venules
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Blood Vessels
Skeletal Muscle Pump:
Vein Valve:
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Blood Vessels
Varicose veins occur if the vein valves become inefficient
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Blood Vessels
Cardiovascular Disorders:
• Leading cause of death in the United States
1) Hypertension = High blood pressure
•  Resistance in vessels =  work for heart
2) Atherosclerosis = Deposits (plaques) collect in vessels
Connective
tissue
Smooth
muscle
Endothelium
Plaque
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(a) Normal artery
50 µm (b) Partly clogged artery
250 µm
Lymph
The lymphatic system
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•
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Coordinates with circulatory
system
Includes:
lymph nodes, vessels, and glands
– Tonsils
contain large numbers of
lymphocytes
– Thymus
matures white blood cells
– Spleen
filters blood
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Lymph
Elephantiasis
Condition caused by
parasitic worm
infection of the
lymphatic system.
Symptoms most
common in legs and
genitals
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Lymph
The lymphatic system
•
Returns fluid to
bloodstream
–
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Lymph capillaries reabsorb
interstitial fluid
Move fats to bloodstream
from small intestine
Bodily defense
–
Contain masses of white
blood cells in nodes
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Lymph
Lymphatic
vessels
•
Narrow, thinwalled
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Cellular
openings act as
one-way valves
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Dead-end in
tissues, collect
materials flow
back to larger
blood vessels
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Thought Question:
If you are an athlete who trains at high elevations, what
happens if you compete at a lower elevation?
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Overview
Living things process energy
• They need oxygen for this - how do they get it?
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Overview
Cellular respiration uses O2 and produces CO2
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C6H12O6 + O2  CO2
+ H2O + ATP energy
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Breathing –
respiration
supports this
process by
exchanging gasses
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Gas Exchange Systems
Exchanging gasses
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Moist surface
–
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Gasses dissolve in water
to move in/out of cells
Thin
Large surface area
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Gas Exchange Systems
Who needs a respiratory system?
•I don’t!
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Moist environment
Small (or thin)
Low energy demand
•I do!
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Dryer environment
Large or thick-bodied
High energy demand
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Gas Exchange Systems
Respiratory systems enable gas
exchange
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Bulk flow
– Fluids move in bulk
– Air/water move to
respiratory surface
– Blood moves through
vessels
Diffusion
– Individual molecules move
down concentration
gradients
– Gas exchange across
respiratory surface
– Gas exchange in tissues
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Gas Exchange Systems
Gills
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Aquatic gas exchange
Delicate folded membranes
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Gas Exchange Systems
Gills facilitate gas exchange in aquatic environments (e.g. fish):
• Elaborately folded ( surface area)
• Contain capillary beds
• Gill size inversely related to [O2]
• Large gills = low [O2]
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Gas Exchange Systems
Fish Efficiency
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Dissolved O2 is < 1%
of water (21% of air)
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Countercurrent
exchange increases
efficiency
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Gas Exchange Systems
Terrestrial respiration
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Internal
– Stay moist &
supported
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Insects have tracheae
– Air enters/exits
through spiracles
– Branching channels
(trachioles) allow gas
exchange with cells
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Gas Exchange Systems
Vertebrate respiration
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Terrestrial use of lungs
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Evolved from accessory
respiratory organs of
freshwater fish
Amphibians are weird
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Remain tied to water
Larval gills to adult lungs
Moist skin transfers
gasses
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Gas Exchange Systems
Reptiles & Mammals use lungs exclusively
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Lack permeable skin
Lungs are more efficient
– Especially birds!
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Mammals
Human Respiration
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Air enters through nose
and mouth to pharynx
Travels through larynx
(voice box)
Epiglottis directs travel
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Human Respiration
On to the lungs
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Trachea 
Bronchi 
Bronchioles
 Alveoli
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Human Respiration
Air is warmed & cleaned
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Dust & bacteria trapped by mucus
Swept up and out by cilia
Microscopic chambers provide
enormous surface area
Surfactant keeps surface moist
Association with capillaries
– Diffusion of gasses
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Lungs
Diffusion
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Blood arrives from
pulmonary artery
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Low in O2
– Higher concentration in
air diffuses into blood
High in CO2
– Higher concentration in
blood diffuses into air
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Transport of gasses
O2 Transport
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Binds to hemoglobin
– Removes O2 from
plasma solution
– Increases
concentration
gradient; favors
diffusion from air
CO binds more tightly to
hemoglobin than O2
Prevents O2 transport
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Transport of gasses
CO2 Transport
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Binds hemoglobin
loosely
Dissolved in plasma
Combines with H20
to form bicarbonate
(HCO3-)
–
More CO2 = lower pH
The Bohr Effect:
Hemoglobin binds more tightly to O2 when pH is
increased and loosely when pH is decreased
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Breathing Mechanisms
The diaphragm helps move air in and out
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Inhalation
– Chest
cavity
expands
– Draws
air in
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Exhalation
– Chest
cavity
shrinks
– Forces
air out
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Breathing Mechanisms
Breathing is involuntary
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Controlled by the respiratory center of the brain
Adjusts breath rate and volume based on sensory input
– Maintain a constant concentration of CO2
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Respiratory Problems
Asthma
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Smooth muscle in bronchioles is excitable and
constricts or spasms
Increased mucus production clogs passages
Can lead to collapse
Some genetic factors,
linked to air quality
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Respiratory Problems
Emphysema
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Alveoli rupture or become brittle
Reduces surface area available for gas
exchange
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Labored and
difficult breathing
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Usually linked
with smoking
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Respiratory Problems
Bronchitis & Pneumonia
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Inflammations of respiratory passages & lungs
Increase in mucus production, decrease in cilia
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Reduces air flow to alveoli
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Causes include bacteria,
viruses, fungi, & parasites
Jim Henson, creator of the Muppets,
died at age 53 from pneumonia
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Respiratory Problems
Tuberculosis
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Bacteria attack and cause lesions on lung tissue
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Smoking
Smoking is BAD
•
Toxins in cigarette smoke cause and/or
exacerbate all of these respiratory
problems in addition with many
others – including lung cancer
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200 different toxins!
– Tar, carbon monoxide,
formaldehyde
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No positive benefits associated
with smoking & many documented
negative health effects
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Lecture 14 concepts
- Describe functions of circulatory and respiratory systems.
- List chambers of human heart – which receive blood, which pump blood?
- Explain the pulmonary circuit – which blood has high / low oxygen?
- List four parts of blood - describe the function of each part (liquid and cells).
- Describe arteries, veins, arterioles, venules, & capillaries.
- What drives blood through arteries? How are veins different?
- What is cardiovascular disease? Give examples.
- Name the parts of the lymphatic system and its role/function.
- In one sentence describe cellular respiration
- Explain bulk flow and diffusion for gas exchange
- Chart the path that air takes into and out of the lungs
- What does carbon monoxide do in the blood stream?
- How does hemoglobin exchange carbon dioxide for oxygen?
- What part of your body controls breathing? How do you pull in a breath?
- List new vocabulary and unknown terms.
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