Transcript blood pressure

Unit 9 End of Year Review
What do animals need to live?
• Animals make energy
using:
– food
– oxygen
food
• Animals build bodies
using:
– food for raw materials
• amino acids, sugars,
fats, nucleotides
ATP
O2
– ATP energy for synthesis
Getting & Using Food
• Ingest
– taking in food
• Digest
– mechanical digestion
• breaking up food into smaller pieces
– chemical digestion
intracellular
digestion
• breaking down food into molecules small
enough to be absorbed into cells
• enzymes (hydrolysis)
• Absorb
– absorb across cell membrane
• diffusion
• active transport
• Eliminate
– undigested extracellular material passes
out of digestive system
extracellular
digestion
mouth
break up food
moisten food
digest starch
kill germs
liver
produces bile
- stored in gall bladder
break up fats
pancreas
produces enzymes to
digest proteins & carbs
stomach
kills germs
break up food
digest proteins
store food
small intestines
breakdown food
- proteins
- starch
- fats
absorb nutrients
large intestines
absorb water
Stomach
• Functions
– food storage
• can stretch to fit ~2L food
– disinfect food
• HCl = pH 2
– kills bacteria
– breaks apart cells
– chemical digestion
• pepsin
– enzyme breaks down proteins
– secreted as pepsinogen
» activated by HCl
But the stomach is made out of protein!
What stops the stomach from digesting itself?
mucus secreted by stomach cells protects
stomach lining
Ooooooh!
Zymogen!
Small intestine
• Function
– major organ of digestion & absorption
– chemical digestion
• digestive enzymes
– absorption through lining
• over 6 meters!
• small intestine has huge surface area = 300m2 (~size of
tennis court)
• Structure
– 3 sections
• duodenum = most digestion
• jejunum = absorption of nutrients & water
• ileum = absorption of nutrients & water
Pancreas
• Digestive enzymes
– peptidases
• trypsin
– trypsinogen
• chymotrypsin
small intestines
– chimotrypsinogen
• carboxypeptidase
– procarboxypeptidase
– pancreatic amylase
• Buffers
– reduces acidity
• alkaline solution rich in bicarbonate
(HCO3-)
Explain how this is a
• buffers acidity of material from
molecular example of
stomach
structure-function theme.
Liver
• Digestive System Functions
– produces bile
• stored in gallbladder until needed
• breaks up fats
– act like detergents to breakup fats
Circulatory System
Connection
bile contains
colors from old
red blood cells
collected in liver =
iron in RBC rusts &
makes feces brown
Absorption by Small Intestines
• Absorption through villi & microvilli
– finger-like projections
• increase surface area for absorption
Ooooh…
Structure-Function
theme!
Absorption of Nutrients
• Passive transport
– fructose
• Active (protein pumps) transport
– pump amino acids, vitamins & glucose
• against concentration gradients across
intestinal cell membranes
• allows intestine to absorb much higher
proportion of nutrients in the intestine than
would be possible with passive diffusion
– worth the cost of ATP!
Large intestines (colon)
• Function
– re-absorb water
• use ~9 liters of water every
day in digestive juices
• > 90% of water reabsorbed
– not enough water absorbed
back to body
» diarrhea
– too much water absorbed back to body
» constipation
respiration for
respiration
Why do we need a
respiratory system?
• Need O2 in
– for aerobic cellular respiration
– make ATP
• Need CO2 out
food
– waste product from
Krebs cycle
O2
ATP
CO2
Optimizing gas exchange
• 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?
Counter current exchange
system
• Water carrying gas flows in one direction,
blood flows in opposite direction
Why does it work
counter current?
Adaptation!
just keep
swimming….
Gas Exchange on Land
• 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?
Medulla monitors blood
• Monitors CO2 level of blood
– measures pH of blood & cerebrospinal fluid
bathing brain
• CO2 + H2O  H2CO3 (carbonic acid)
• if pH decreases then
increase depth & rate
of breathing & excess
CO2 is eliminated in
exhaled air
Hemoglobin
• 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
Circulatory systems
• All animals have:
– circulatory fluid = “blood”
– tubes = blood vessels
– muscular pump = heart
open
hemolymph
closed
blood
Vertebrate circulatory system
• Adaptations in closed system
–2 number of heart3 chambers differs
4
low
pressure
to body
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
Evolution of 4-chambered heart
• 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
systemic
Mammalian
circulation
pulmonary
systemic
What do blue vs. red areas represent?
Cardiac cycle
• 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
•
Arteries: Built for high pressure
Arteries
pump
– thicker walls
• provide strength for high pressure
pumping of blood
– narrower diameter
– elasticity
• elastic recoil helps
maintain blood
pressure even
when heart relaxes
•
Veins: Built for low pressure
Blood flows
flow
toward heart
Veins
– thinner-walled
– wider diameter
Open valve
• blood travels back to heart
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
allow blood to flow only toward heart
Capillaries: Built for exchange
• Capillaries
– very thin walls
• lack 2 outer wall layers
• only endothelium
– enhances exchange
across capillary
– diffusion
• exchange between blood
& cells
Exchange across capillary walls
Fluid & solutes flows
out of capillaries to
tissues due to blood
pressure
• “bulk flow”
Lymphatic
capillary
Interstitial fluid flows
back into capillaries
due to osmosis
 plasma proteins  osmotic
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
Animals
poison themselves
from the inside
by digesting
proteins!
Intracellular Waste
• What waste products?
– what do we digest our food into…
•
•
•
•
 CO2 + H2O
lots!
carbohydrates = CHO
 CO2 + H2O
lipids = CHO
 CO2 + H2O + N
proteins = CHON
 CO2 + H2O + P + N
nucleic acids = CHOPN
cellular digestion…
cellular waste
NH2 =
ammonia
H| O
||
H
N –C– C–OH
|
H
R
very
little
CO2 + H2O
Nitrogen waste
 Aquatic organisms


can afford to lose water
ammonia
 most toxic
 Terrestrial


need to conserve
water
urea
 less toxic
 Terrestrial egg
layers



need to conserve water
need to protect
embryo in egg
uric acid
 least toxic
Mammalian System
blood
filtrate
• Filter solutes out of blood &
reabsorb H2O + desirable solutes
• Key functions
– filtration
• fluids (water & solutes) filtered out
of blood
– reabsorption
• selectively reabsorb (diffusion) needed
water + solutes back to blood
– secretion
• pump out any other unwanted solutes to
urine
– excretion
• expel concentrated urine (N waste +
solutes + toxins) from body
concentrated
urine
How can
Mammalian kidney
different sections
allow the diffusion
of different
molecules?
• Interaction of circulatory
& excretory systems
• Circulatory system
– glomerulus =
ball of capillaries
Bowman’s
capsule
Proximal
tubule
Distal
tubule
Glomerulus
• Excretory system
– nephron
– Bowman’s capsule
– loop of Henle
•
•
•
•
proximal tubule
descending limb
ascending limb
distal tubule
– collecting duct
Glucose
Amino
acids
H2O
Mg++ Ca++
H2O
Na+ ClH2O
H2O
Na+ Cl-
H2O
H2O
Loop of Henle
Collecting
duct
Nephron: Filtration
• At glomerulus
– filtered out of blood
•
•
•
•
H2O
glucose
salts / ions
urea
– not filtered out
• cells
• proteins
high blood pressure in kidneys
force to push (filter) H2O & solutes
out of blood vessel
BIG problems when you start out
with high blood pressure in system
hypertension = kidney damage
Nephron: Re-absorption
• Proximal tubule
– reabsorbed back into blood
• NaCl
– active transport
of Na+
– Cl– follows
by diffusion
• H2O
• glucose
• HCO3– bicarbonate
– buffer for
blood pH
Descending
limb
Ascending
limb
Nephron: Re-absorption
 Loop of Henle

structure fits
function!
descending limb
 high permeability to
H2O
 many aquaporins in
cell membranes
 low permeability to
salt
 few Na+ or Cl–
channels

reabsorbed
 H2O
Descending
limb
Ascending
limb
Nephron: Re-absorption
 Loop of Henle

structure fits
function!
ascending limb
 low permeability
to H2O
 Cl- pump
 Na+ follows by
diffusion
 different membrane
proteins

reabsorbed
 salts
 maintains osmotic
gradient
Descending
limb
Ascending
limb
Nephron: Re-absorption
 Distal tubule

reabsorbed
 salts
 H2O
 HCO3 bicarbonate
Nephron: Reabsorption & Excretion
 Collecting duct

reabsorbed
 H2O

excretion
 concentrated
urine passed
to bladder
 impermeable
lining
Descending
limb
Ascending
limb
Osmotic control in nephron
• How is all this re-absorption achieved?
– tight osmotic
control to reduce
the energy cost
of excretion
– use diffusion
instead of
active transport
wherever possible
the value of a
counter current
exchange system
why
Summary
selective reabsorption
& not selective
filtration?
• Not filtered out
– cells
 proteins
– remain in blood (too big)
• Reabsorbed: active transport
– Na+
– Cl–
amino acids
 glucose

• Reabsorbed: diffusion
– Na+
– H2O

Cl–
• Excreted
– urea
– excess H2O
 excess solutes (glucose, salts)
– toxins, drugs, “unknowns”
Blood Osmolarity
ADH
pituitary
increased
water
reabsorption
increase
thirst
nephron
high
blood osmolarity
blood pressure
low
ADH =
AntiDiuretic Hormone
Blood Osmolarity
Oooooh,
zymogen!
JGA =
JuxtaGlomerular
Apparatus
high
blood osmolarity
blood pressure
adrenal
gland
low
increased
water & salt
reabsorption
in kidney
JGA
nephron
renin
aldosterone
angiotensinogen
angiotensin
Blood Osmolarity
ADH
increased
water
reabsorption
pituitary
increase
thirst
nephron
high
blood osmolarity
blood pressure
adrenal
gland
low
increased
water & salt
reabsorption
JuxtaGlomerular
Apparatus
nephron
renin
aldosterone
angiotensinogen
angiotensin