Transcript AP Circulatory

Circulation
Chapter 38
General Function
1. Transports nutrients (from digestion),
wastes (to respiratory and urinary),
hormone (endocrine) and gases (to and
from respiratory) throughout the body
2. Helps fight infection
3. Helps regulate body temperature and
pH
Functional Connections
food, water intake
oxygen intake
DIGESTIVE
SYSTEM
nutrients,
water,
salts
RESPIRATORY
SYSTEM
oxygen
elimination
of carbon
dioxide
carbon
dioxide
CIRCULATORY
SYSTEM
URINARY
SYSTEM
water,
solutes
elimination
of food
residues
rapid transport
to and from all
living cells
elimination of
excess water,
salts, wastes
Figure 38.2
Page 665
Circulatory Systems
Open System
•Arthropods and most mollusks
Closed System
•Vertebrates and anelids
pump
pump
spaces or
cavities
in body
tissues
aorta
heart
Figure 38.3
Page 666
Circulation of higher animals- Heartpump to move fluids-usually one way
with a valve
Closed circulatory system- one that has
vessels (veins and arteries) to move the
blood
Open circulatory system- lacking vesselsallowing the blood to move in large
sinuses
Open circulatory systems:
Insect circulatory system (picture)
Closed circulatory systems:
Earthworm
Anterior end--10 hearts (aortic arches)
(5 on each side)
Vertebrate Circulatory
Arteries- take blood away from the heart
Veins- take blood to the heart
Capillaries- connect arteries and veins
(exchanges materials)
Fish
1 circuit , 2 chambered heart
Amphibians
2 circuits (to
lungs and body),
3 chambered
heart (blood
mixes)
3. Reptiles- 3 chambered heart; 2 atria, 1
ventricle but the ventricle is partial
divided allowing very little mixing of
blood
Birds and mammals – 2 circuits (to lungs
and body), 4 chambered heart (blood
doesn’t mix)
Functions of Blood
• Transports oxygen and nutrients to cells
• Carries carbon dioxide and wastes away
from cells
• Helps stabilize internal pH
• Carries infection-fighting cells
• Helps equalize temperature
Components of Blood
See figure 38.7, page 669 also
Blood
6-8%
of body
weight
Plasma portion (50-60% of total volume)
• Water
• Proteins
• Ions, sugars, lipids, amino acids,
hormones, vitamins, dissolved gases
Cellular portion (40-50% of total volume)
• White blood cells (leukocytes) – involved in immune response
Neutrophils-fast acting phagocytes, nonspecific
Lymphocytes-B & T cells, specific
Monocytes-call up immune response, slow, nonspecific
Eosinophils-fast, secrete enzymes, nonspecific
Basophils-fast, inflammatory response, nonspecific
• Red blood cells (erythrocytes) – carry oxygen
• Platelets – involved in clotting
Figure 38.5
Page 668
Erythrocytes (Red Cells)
• Most numerous cells in the blood
• Transport oxygen and carbon dioxide
• Colored red by oxygen-binding pigment
(hemoglobin)
• Have no nucleus when mature
• Develop from stem cells in bone marrow
• Good for about 120 days, ongoing
replacement
Biconcave disc
Leukocytes (White Cells)
• Function in housekeeping and defense
• Cell types
Basophils
Eosinophils
B lymphocytes
Neutrophils
T lymphocytes
Macrophages
NK cells
Dendritic cells
Mast cells
Leukocytes (White Cells)
Platelets (thrombocytes)
• Membrane-bound cell fragments
• Derived from megakaryocytes, which
arise from stem cells
• Release substances that initiate blood
clotting
Blood Cell Development
• Stem cells in bone marrow are
unspecialized cells that retain the
capacity to divide
• Some daughter cells of stem cells
differentiate to form blood cells
• Body must continually replace blood
cells
natural
killer cells
mast cells
neutrophils
eosinophils
basophils
forerunners of
the white blood
cells (leukocytes)
committed cell
stem cells that (proerythroblast)
?
multiply and
differentiate in
bone marrow
T lymphocytes
(mature in
thymus)
B lymphocytes
(mature in bone
marrow)
monocytes
(immature
phagocytes)
red blood cells
(ertyrocytes)
dendritic cells
megakaryocytes
mature
macrophages
platelets
Fig. 38-5, p.661
Blood Disorders
• Red blood cell disorders
– Anemia – to few red-blood cells, oxygen blood
levels cannot be kept high enough
• Many different kinds, from many causes
– Polycythemias – too many red-blood cells,
makes blood flow sluggish
• White blood cell disorders
– Infectious mononucleosis – too many
monocytes and lymphocytes
– Leukemias – cancer suppresses or impairs
white blood cell formation in bone marrow
Blood Type in Transfusions
• Require that donor and recipient have
same blood type
• If bloods of incompatible types are mixed,
recipient’s immune system will attack,
clump up and destroy donor cells
• This is an agglutination reaction
ABO Blood Type
• Type A red cells have one type of marker
at surface (can accept type A or O)
• Type B red cells have a different type of
marker (can accept type B or O)
• Type AB cells have both markers (tolerate
any donor)
• Type O cells have neither marker (can
only accept type O donor)
Blood Type Compatibility
Blood type of donor
O
A
B
AB
O
Blood type of
recipient
A
B
AB
Figure 38.8
Page 670
Rh Blood Type
• Based on presence or absence of Rh
marker on red cells
– Rh+ has marker, Rh- doesn’t have marker
• Can cause problems during pregnancy
– If mother is Rh negative,
– has previously carried Rh positive child,
– is carrying fetus that is Rh positive
– Mother’s antibodies can attack fetal cells
Vessels
•Blood flows from heart into arteries (large vessels that
lead away from the heart)
•Then into arterioles (smaller vessels that lead away from
the heart)
•Then into capillaries (smallest diameter, with thin walls
that allow for diffusion of materials into and out of
blood)
•Then into venules (small vessels that lead back toward
the heart)
•And finally into veins (large diameter vessels that return
blood to heart)
Blood Vessels
• Arteries: main
transporters of
oxygenated blood,
thick elastic walls
to withstand high
pressure
Figure 38.15 Page 676
Blood Vessels
• Arteries: main
transporters of
oxygenated blood
• Arterioles: diameter
is adjusted to
regulate blood flow
• Capillaries: diffusion
occurs across thin
walls
Figure 38.1
Blood Vessels
Human Heart Is a
Double Pump
• Partition separates heart into
left and right sides
• Each pumps blood through a
different circuit
Pulmonary Circuit
right pulmonary artery
Short loop that
oxygenates
blood, pumps
blood to and
from lungs.
capillary
bed of
right
lung
left pulmonary artery
capillary bed
of left lung
pulmonary
trunk
(from
systemic
circuit)
pulmonary
veins
heart
Figure 38.10
Page 672
(to systemic circuit)
lungs
Systemic
Circuit
Longer loop that
carries blood to
and from body
tissues
capillary beds of head
and upper extremities
(to pulmonary
circuit)
aorta
(from
pulmonary
circuit)
heart
capillary beds of other
organs in thoracic cavity
capillary bed of liver
capillary beds of intestines
Figure 38.10
Page 672
Hepatic Portal System
• Carries blood from capillaries in
digestive organs to capillaries in the
liver
• Allows liver to detoxify substances from
digestive tract before they are carried to
the body
Major
Vessels
carotid arteries
jugular veins
ascending aorta
superior vena cava
pulmonary veins
hepatic portal vein
renal vein
inferior vena cava
iliac veins
femoral vein
pulmonary arteries
coronary arteries
brachial artery
renal artery
abdominal aorta
iliac arteries
femoral artery
Figure 38.11 Page 673
Location of the Heart
right lung
left lung
Figure 38.12
Page 674
rib cage
diaphragm
Pericardium – double sac of tough connective
tissue that protects and anchors the heart to
nearby structures
Figure 38.12
Page 674
Four Chambers
• Each side has two chambers
– Upper atrium
– Lower ventricle
• Valves between atria and
ventricles (AV valves)
• Valves between each ventrical
and artery (semilunar)
• Contraction of the ventricles is
the driving force for blood
circulation.
Figure 38.12
Page 674
arch of aorta
superior vena cava
trunk of
pulmonary
arteries
left semilunar
valve
Heart Anatomy
right semilunar valve
left pulmonary
veins
left atrium
right pulmonary veins
right atrium
left AV valve
right AV valve
right ventricle
left ventricle
endothelium and
connective tissue
inferior vena cava
inner layer of
pericardium
septum
myocardium
heart’s
apex
Figure 38.12
Page 674
Blood Path
•
•
•
•
•
From body in vena cava
To right atrium
To right ventricle
To lungs (in pulmonary artery – deoxygenated)
To left atrium from lungs (in pulmonary vein –
oxygenated)
• To left ventricle
• To body in aorta
Cardiac Muscle
•Cardiac muscle is striated, like skeletal muscles.
•Sliding filament model like skeletal muscles.
•But cardiac muscle cells are branching, short and
connected at their endings
•Lots of gap junctions are present allowing quick
spread of action potentials.
•Also, 1% of cardiac muscles do not contract, they
function in the cardiac conduction system (make the
heart pump by rhythmic waves of excitation).
one
sarco
mere
mitochon
drion
intercalated
disk
Intercalated disk,
a region of
Fig. 38-15a,b, p.667
c Gap
junction.
These
communicati
on junctions
occur on the
sides of
cardiacFig. 38-15c, p.667
Conduction and Contraction
•Systole – contraction
• SA node in right atrium is
pacemaker
• Electrical signals cause
contraction of atria
• Signal flows to AV node
and down septum to
ventricles, causing the
ventricals to contract.
• The nervous can only
adjust the rate and
strength of contractions.
Figure 38.14
Page 675
•Diastole - relaxation
SA node
AV node
Blood Pressure
• Highest in arteries,
lowest in veins
• Systolic pressure is
peak pressure
(ventricular
contraction)
• Diastolic pressure is
the lowest
 Greatest pressure drop
is in arteriolesFigure 38.1
Controlling Blood Pressure
• Cardiac output is adjusted by controls over rate and strength
of heartbeat (nervous system)
• Total resistance in vessels changes due to diameter changes
(vasoconstriction and vasodilation) which is controlled by the
nervous and endocrine system.
• Baroreceptor response is main short-term control of blood
pressure
– By triggering the sympathetic or parasympathetic nerves
that control the blood vessels and heart
• Kidneys are the main long-term control of blood pressure
– By regulating the volume and composition of the blood
Velocity of Flow Varies
• Volume of blood flowing through vessels
always has to equal heart’s output
• Flow velocity is highest in large-diameter
transport vessels
• Flow velocity is slowest in capillary beds;
blood spreads out into many vessels with
greater total cross-sectional area
Diffusion Zone
• Capillary beds are the site of exchange
between blood and interstitial fluid
• Capillary is a single sheet of epithelial
cells
• Flow is slow; allows gasses to diffuse
across membranes of blood cells and
across endothelium
Movement in and out Capillaries
• Capillary beds are the site of exchange between
blood and interstitial fluid
• Capillary is a single sheet of epithelial cells (very thin
walls), some clefts between them, flow is slow
• allows gasses to diffuse across membranes of blood
cells and across endothelium
• Some proteins leave and enter by endo and
exocytosis
• Some ions leave at the clefts between the cells
• Bulk flow (in response to fluid pressure) also occurs
– Ultrafiltration out and reabsorption in
Bulk Flow in Capillary Bed
blood to
venule
blood
from
arteriole
outward-directed inward-directed
bulk flow
osmotic movem
cells of
tissue
Figure 38.
Net Bulk Flow
• Normally, ultrafiltration only slightly
exceeds reabsorption
• Fluid enters interstitial fluid and is
eventually returned to blood by way of the
lymphatic system
• High blood pressure causes excessive
ultrafiltration and results in edema
The Venous System
• Blood flows from capillaries into venules, then
on to veins
• Veins are large-diameter vessels with some
smooth muscle in wall
• Valves in some veins prevent blood from
flowing backward
Figure 3
Bicarbonate Formation
CO2 + H2O
H2CO3
carbonic acid
HCO3– + H+
bicarbonate
• Most carbon dioxide is transported
as bicarbonate
• Some binds to hemoglobin
• Small amount dissolves in blood
Cardiovascular Disorder
•Hypertension
High Blood pressure (above 140/90)
Atherosclerosis
• Arteries thicken, lose elasticity, and fill up with cholesterol
and lipids
Arrhythmias
• Irregular heartbeat
Risk factors
• Smoking, Gender (maleness), Genetic factors, Old age,
High cholesterol, Obesity, Lack of exercise, Diabetes
mellitus
Hemostasis – stops bloodloss
• Blood vessel spasm (contracts, slows
bloodflow), platelet plug formation,
blood coagulation (clotting)
• Clotting mechanism
– Prothrombin is converted to thrombin
– Fibrinogen is converted to fibrin
– Fibrin forms net that entangles cells
and platelets
Fig. 38-23, p.672
Lymphatic System
• Collects and returns fluid to the bloodstream
– The circulatory system is leaky
– Some fluid is forced out of the smallest vessels and
into the interstitial fluid
– Vessels of the lymphatic system pick up this fluid,
filter it, and return it to the circulatory system
• Defends against infection
Main Parts- See figure page 683
• Lymph nodes – organ acts as a filter for lymph, packed
with lymphocytes for immune response
• Lymph vessels – tubes that collect and deliver leaky
fluid back to vein in lower neck
• Lymph – the fluid
• Lymphoid organs – central to body’s defense
– Tonsils, Thymus, Spleen
Lymph Nodes
• Located at intervals
along lymph vessels
• Act as a filter for lymph
• Contain lymphocytes
that can recognize a
foreign invader
Figure 38.2
Lymphoid Organs
• Central to the
body’s defense
• Tonsils
• Spleen
• Thymus gland
Figure 38.2