Transcript blood pressure - Cloudfront.net

Enzymes are a huge part of digestion
a)
b)
Describe structure and function of an
enzyme
How are enzymes tied to digestion?
alveoli
gills
Gas Exchange
Respiratory Systems
elephant
seals
2008-2009

Need O2 in
◦ for aerobic cellular respiration
◦ make ATP

Need CO2 out
◦ waste product from
Krebs cycle
food
O2
ATP
CO2

O2 & CO2 exchange between
environment & cells
◦ need moist membrane
◦ need high surface area

Why high surface area?
◦ maximizing rate of gas exchange
◦ CO2 & O2 move across cell membrane by diffusion
 rate of diffusion proportional to surface area

Why moist membranes?
◦ moisture maintains cell membrane structure
◦ gases diffuse only dissolved in water
High surface area?
High surface area!
Where have we heard that before?
Aquatic organisms
external systems with lots of
surface area exposed to
aquatic environment
Terrestrial
moist internal respiratory
tissues
with lots of surface area
Exchange tissue:
spongy texture, honeycombed with
moist epithelium
Why is this exchange
with the environment
RISKY?



Larynx (upper part of
respiratory tract)
Vocal cords (sound
production)
Trachea (windpipe)




Bronchi (tube to lungs)
Bronchioles
Alveoli (air sacs)
Diaphragm (breathing
muscle)

Gas exchange across thin epithelium of
millions of alveoli
◦ total surface area in humans ~100 m2

Breathing due to changing pressures in lungs
◦ air flows from higher pressure to lower pressure
◦ pulling air instead of pushing it
1)
Share plan with tablemates to get A or B on
all April quizzes
2) Change Sat, April 21 to Sat, April 14th
3) Come up with a structure is ties to function
example

Water carrying gas flows in one direction,
blood flows in opposite direction
Why does it work
counter current?
Adaptation!
just keep
swimming….
70%
100
%
front
40%
back
15%
water
60%
30%
90% counter5%
current
blood
50% 70%
50% 30%
concurrent

100
%
water
5%
blood
Blood & water flow in opposite directions
◦ maintains diffusion gradient over whole length
of gill capillary
◦ maximizing O2 transfer from water to blood

Advantages of terrestrial life
◦ air has many advantages over water
 higher concentration of O2
 O2 & CO2 diffuse much faster through air
 respiratory surfaces exposed to air do not have to
be ventilated as thoroughly as gills
 air is much lighter than water & therefore much
easier to pump
 expend less energy moving air in & out

Disadvantages
◦ keeping large respiratory surface moist
causes high water loss
 reduce water loss by keeping lungs internal
Why don’t
land animals
use gills?
Tracheae


air tubes branching throughout
body
gas exchanged by diffusion
across moist cells lining
terminal ends, not through
open circulatory system

Air enters nostrils
◦ filtered by hairs, warmed & humidified
◦ sampled for odors

Pharynx  glottis  larynx (vocal cords)
 trachea (windpipe)  bronchi 
bronchioles  air sacs (alveoli)
Epithelial lining covered by
cilia & thin film of mucus
◦ mucus traps dust, pollen,
particulates
◦ beating cilia move mucus upward
to pharynx, where it is swallowed
QuickTime™ and a
ompressed) decompressor
eded to see this picture.


ATP
Homeostasis
◦ keeping the internal environment of the
body balanced
◦ need to balance O2 in and CO2 out
◦ need to balance energy (ATP) production

Exercise
◦ breathe faster
 need more ATP
 bring in more O2 & remove more CO2

O2
Disease
◦ poor lung or heart function = breathe faster
 need to work harder to bring in O2 & remove CO2
CO

Why use a carrier molecule?
◦ O2 not soluble enough in H2O for animal needs
 blood alone could not provide enough O2 to animal
cells
 hemocyanin in insects = copper (bluish/greenish)
 hemoglobin in vertebrates = iron (reddish)

Reversibly binds O2
◦ loading O2 at lungs or gills & unloading at cells
heme group
cooperativity

Binding O2
◦ binding of O2 to 1st subunit causes shape
change to other subunits
 conformational change
◦ increasing attraction to O2

Releasing O2
◦ when 1st subunit releases O2,
causes shape change to
other subunits
 conformational change
◦ lowers attraction to O2

Dissolved in blood plasma as bicarbonate ion
Tissue cells
carbonic acid
CO2 + H2O  H2CO3
CO2
carbonic
anhydrase
bicarbonate
H2CO3  H+ + HCO3–
CO2 dissolves
in plasma
CO2 combines
with Hb
Plasma
Carbonic
anhydrase
CO2 + H2O H2CO3
H2CO3
H+ + HCO3–
Cl–
HCO3–

Lower CO2
pressure at lungs
allows CO2 to
diffuse out of
blood into lungs
Lungs: Alveoli
CO2
CO2 dissolved
in plasma
CO2 + H2O
H2CO3
–
+
3 + H
Hemoglobin + COHCO
2
H2CO3
Plasma
HCO3–Cl–
 Circulation
and Gas
Exchange

Animal cells exchange material across their
cell membrane
◦
◦
◦
◦

fuels for energy
nutrients
oxygen
waste (urea, CO2)
If you are a 1-cell organism that’s easy!
◦ diffusion

If you are many-celled that’s harder

What needs to be transported
◦ nutrients & fuels
 from digestive system
◦ respiratory gases
 O2 & CO2 from & to gas exchange systems: lungs, gills
◦ intracellular waste
 waste products from cells
 water, salts, nitrogenous wastes (urea)
◦ protective agents
 immune defenses
 white blood cells & antibodies
 blood clotting agents
◦ regulatory molecules
 hormones

All animals have:
◦ circulatory fluid = “blood”
◦ tubes = blood vessels
◦ muscular pump = heart
open
hemolymph
closed
blood

Taxonomy
◦ invertebrates
 insects,
arthropods,
mollusks

Structure
◦ no separation
between blood &
interstitial fluid
 hemolymph

Taxonomy
◦ invertebrates
 earthworms, squid,
octopuses
◦ vertebrates

Structure
◦ blood confined to
vessels & separate
from interstitial fluid
 1 or more hearts
 large vessels to
smaller vessels
 material diffuses
between blood vessels
& interstitial fluid
closed system = higher pressures

Adaptations in closed system
◦ number of heart chambers differs
2
low
pressure
to body
3
4
low O2
to
body
high
pressure
& high O2
to body
What’s the adaptive value of a 4 chamber heart?
4 chamber heart is double pump = separates oxygen-rich &
oxygen-poor blood; maintains high pressure



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

Selective forces
◦ increase body size
 protection from predation
 bigger body = bigger stomach for
herbivores
◦ endothermy
 can colonize more habitats
◦ flight
 decrease predation & increase prey
capture

Effect of higher metabolic rate
◦ greater need for energy, fuels, O2,
waste removal
 endothermic animals need 10x energy
 need to deliver 10x fuel & O2 to cells
convergent
evolution

Chambered heart
◦ atrium = receive blood
◦ ventricle = pump blood out

Blood vessels
◦ arteries = carry blood away from heart
 arterioles
◦ veins = return blood to heart
 venules
◦ capillaries = thin wall, exchange / diffusion
 capillary beds = networks of capillaries
Blood vessels
arteries
veins
artery
venules
arterioles
arterioles
capillaries
venules
veins

Arteries
◦ thicker walls
 provide strength for high
pressure pumping of blood
◦ narrower diameter
◦ elasticity
 elastic recoil helps
maintain blood
pressure even
when heart relaxes

Veins
Blood flows
◦ thinner-walled
toward heart
◦ wider diameter
 blood travels back to heartOpen valve
at low velocity & pressure
 lower pressure
 distant from heart
 blood must flow by skeletal
muscle contractions when we
move
Closed valve
 squeeze blood through
veins
◦ valves
 in larger veins one-way valves

Capillaries
◦ very thin walls
 lack 2 outer wall layers
 only endothelium
 enhances exchange across
capillary
◦ diffusion
 exchange between blood &
cells

Blood flow in capillaries controlled by
pre-capillary sphincters
 supply varies as blood is needed
 after a meal, blood supply to digestive tract increases
 during strenuous exercise, blood is diverted from digestive
tract to skeletal muscles
◦ capillaries in brain, heart, kidneys & liver usually
filled to capacity
sphincters open
sphincters closed
Fluid & solutes flows
out of capillaries to
tissues due to blood
pressure

Lymphatic
capillary
Interstitial fluid flows
back into capillaries
due to osmosis
 plasma proteins  osmotic
“bulk flow”
pressure in capillary
BP > OP
BP < OP
Interstitial
fluid
What about
edema?
Blood
flow
85% fluid returns
to capillaries
Capillary
Arteriole
15% fluid returns
via lymph
Venule

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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)

Parallel circulatory system
◦ transports white blood cells
 defending against infection
◦ collects interstitial fluid &
returns to blood
 maintains volume & protein
concentration of blood
 drains into circulatory system
near junction of vena cava &
right atrium
Production & transport of WBCs
Traps foreign invaders
lymph vessels
(intertwined amongst blood vessels)
lymph node
to neck & head
& arms
Coronary arteries
systemic
pulmonary
systemic
What do blue vs. red areas represent?
bypass surgery

http://www.smm.org/heart/heart/pumping.h
tm


4 valves in the heart
◦ flaps of connective tissue
◦ prevent backflow
Atrioventricular (AV) valve
◦ between atrium & ventricle
◦ keeps blood from flowing back
into atria when ventricles contract
 “lub”

SL
Semilunar valves
◦ between ventricle & arteries
◦ prevent backflow from arteries into
ventricles while they are relaxing
 “dub”
AV
AV

Heart sounds
◦ closing of valves
◦ “Lub”
 recoil of blood against
closed AV valves
◦ “Dub”
 recoil of blood against
semilunar valves

SL
AV
AV
Heart murmur
◦ defect in valves causes hissing sound when
stream of blood squirts backward through valve

1 complete sequence of pumping
◦ heart contracts & pumps
◦ heart relaxes & chambers fill
◦ contraction phase
 systole
 ventricles pumps blood out
◦ relaxation phase
 diastole
 atria refill with blood
systolic
________
diastolic
pump
(peak pressure)
_________________
fill (minimum pressure)
110
____
70

High Blood Pressure (hypertension)
◦ if top number (systolic pumping) > 150
◦ if bottom number (diastolic filling) > 90







Cardiovascular disease
(>50% 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


Demonstrate the path of an O2 molecule
from the air to a knee cell as it travels
through the respiration system and the
circulatory system (travelling on a red
blood cell). Make sure to include arteries,
capillaries and/or veins.
Demonstrate the path of an CO2 molecule
from a knee cell to the air as it travels
through the respiration system and the
circulatory system (travelling on a red
blood cell). Make sure to include arteries,
capillaries and/or veins.
 All
members verbally
involved
 8 or more different props
 Creativity
 Accurate description
 Kinesthetic