Transcript Contributions of the Circulatory System

Circulatory and
Lymphatic System
Contributions of the Circulatory
System
• *Nutritive: provides cells with food (nutrients)
• *Excretory: provides for elimination of wastes
• *Protection: provides for defense and resistance
to disease
• *Regulatory: provides for internal balance of
heat and fluids
• *Respiratory: provides cells with O2 and the
elimination of CO2
**It’s the transportation system of the
body!**
Characteristics of Blood
• Blood is a fluid connective
tissue
• Composition of blood:
• 45% blood cells (formed
elements)
• 55% plasma (liquid portion)
• Blood contains 3 types of cells:
• Red Blood Cells
(RBC/erythrocytes)
• White Blood Cells
(WBC/leukocytes)
• Platelets (thrombocytes)
• Plasma
• *Amount in an adult
• 4-6 quarts
Plasma
• Liquid part of blood
• 91.5% water
• 7% plasma proteins
• Other 1.5 %: salts,
nutrients, electrolytes,
hormones, respiratory
gases, nitrogenous
wastes, antibodies….
• Plasma also carries
body heat
Erythrocytes (RBC’s)
• Normal range of RBC 4-6
million cells
• RBC’s contain protein
hemoglobin: the part of the
RBC that carries oxygen
• Function of RBCs: carry
oxygen to all body tissues
• Normal range for
hemoglobin 12-18 grams
per 100cc’s of blood
• Iron = mineral needed for
formation of hemoglobin
Leukocytes (white blood cells/WBC)
• Normal WBC count = 5,000 to
10,000 cells per mm3
• Function of WBCs: defend
against infection and help
provide immunity
• Formed in red blood marrow
and lymphatic tissue
• Elevation of different WBCs
help to diagnose specific
problems
Thrombocytes (Platelets)
• Platelets are not whole cells;
they are fragments or pieces
of cells
• Function of platelets: aid in
blood clotting
• Normal platelet count:
250,000 to 400,000 cells per
mm3
• Platelets are necessary for
homeostasis (prevention of
blood loss)
Blood Types
• Our blood type is genetic
• A type and cross match is
done before a blood
transfusion to prevent
transfusing incompatible
blood
• Type A blood
• Has A antigen on RBCs
• Has anti-B antibodies in
plasma
• Type B blood
• Has B antigen on RBC’s
• Has anti-A antibodies in
plasma
Blood Types
• Type AB blood
• Has both A&B antigen on RBCs
• Has no antibodies in plasma
(neither anti-A or anti-B
antibodies)
• ***Universal recipient (no
antibodies)***
• Type O blood
• Has no antigen on RBCs (no A
or B antigen)
• Has anti-A and anti-B
antibodies in plasma
• ***Universal donor (no
antigens)***
Rh Factor
• Rh factor is another antigen
that may be present on
RBCs
• If the Rh factor antigen is
present, the person is Rh+
• If the Rh factor antigen is
not present, the person is
Rh• Problem: Rh incompatibility
between mother (-) and
fetus (+): hemolytic anemia
Hemostasis
• Involves 3 events:
• Vascular spasm: a sudden, brief
tightening of a blood vessel. Vascular
spasms can temporarily reduce blood
flow to tissues supplied by that vessel.
• Platelet plugs: platelets clump
together at the site of injury, swell,
and stick to the injured area, acting as
a plug to reduce the bleeding.
• Chemical clotting: Platelets, which
come from white blood cell fragments,
immediately begin to adhere to the
cut edges of the vessel and release
chemicals to attract even more
platelets. A platelet plug is formed,
and the external bleeding stops.
Antigens and Antibodies
• Antigen: Substance that
stimulates the body to
make antibodies,
usually foreign, except
proteins present on
RBCs
• Antibody: Proteins
produced by the body
to neutralize antigens
The Heart
• Cone shaped, hollow
muscular organ
• Beats 100,000 times/day
• Located in the mediastinum
• The thoracic cavity
• Primary function: pump
blood through arteries,
capillaries, and veins
• Animation
Pericardial Membranes
• *The heart is enclosed
in the pericardium (or
pericardial membranes)
Walls of the Heart
• 3 Distinct Layers
• 1. Epicardium
• 2. Myocardium- thick
muscular wall of the
heart
• 3.Endocardium
Heart Chambers
• Upper chambers of the heart –
atria-Right and left atrium
• Thin walls
• Separated by interatrial septum
• Common wall of myocardium
• Atria are receiving chambers for
blood
• Lower chambers of heart –
ventricles-Right and left
ventricles
Septum
Right Atrium
• 2 large veins return blood
from body to right atrium of
the heart
• Superior vena cava
• Carries blood from upper
body to heart
• Inferior vena cava
• Carries blood from lower
body to heart
• *Largest vein in the body
Left Atrium
• *4 pulmonary veins
return blood from the
lungs to the left atrium
of the heart
Right Ventricle
• Receives blood from the
right atrium
• Pulmonary artery
• *Pulmonary artery
takes blood from the
right ventricle to the
lungs. It branches into
left and right
pulmonary arteries, one
for each lung.
*Tricuspid
Value*
Right atrium
to right
ventricle
Left Ventricle
• Receives blood
from left atrium
• *Thickest walls
• Pumps blood to
body via aorta =
largest artery of
the body
• Mitral valve
• Blood is carried to
the lungs by the
pulmonary artery
Heart Valves
• Tricuspid/right
atrioventricular (AV) valve
• Blood flows from right atrium
through this valve into right
ventricle
• Mitral / bicuspid / left AV
valve
• *Blood flow from left atrium
(auricle) through this valve
into left ventricle
Heart Valves
• Pulmonary semilunar valve
• Valve at the junction of the
right ventricle and the
pulmonary artery
• Aortic semilunar valve
• Valve at junction of aorta and
left ventricle
Cardiac Conduction System
• Cardiac cycle regulated by electrical
activity of myocardium
• Heart generates its own beat and the
electrical impulses follow a specific
route
• SA Node in right atrium is the
*pacemaker*
• Initiates each heartbeat
• *Conduction Pathway: SA Node->
1.AV Node-> atrial myocardium (atria
contract)-> 2.Bundle of HIS-> right
and left bundle branches-> 3.Purkinje
fibers-> ventricular myocardium
(ventricles contract)
• http://www.mhhe.com/biosci/ap/dy
namichuman2/content/cardio/VPL29.MOV
Nervous System Control of the
Heart
•
•
•
•
Cardiac muscle is involuntary in action
Control center is in the brain (medulla)
ANS = Sympathetic and Parasympathetic divisions
*Sympathetic division of the ANS speeds the heart rate
(adrenaline)
• *Parasympathetic division of the ANS slows and strengthens
the heart rate
Heart’s Pumping Cycle
• Atria contract forcing blood into
ventricles
• Ventricles contract forcing blood
out of the heart
• Right Ventricle: blood pumped
out of the pulmonary artery to
lungs to be oxygenated
• Left Ventricle: blood pumped out
of the aorta to the body
• Blood fills both atria
• Right atrium: from body
• Left atrium: from lungs
Heart Sounds
• Each heartbeat produces 2
sounds: lub-dub
• Lub-dub sound = closing of heart
valves
• *First sound: lub = closing of
valves between atria and
ventricles (AV valves) caused by
ventricular sound
• *Second sound: dub = closing of
aortic and pulmonary semilunar
valves
• Heart murmur: an abnormal or
extra heart sound caused by a
malfunctioning heart valve
Cardiac Cycle
• Sequence of events in 1 heartbeat
• Simultaneous contraction of the two atria followed (the “lub”
sound) by simultaneous contraction of the two ventricles (the
“dub” sound)
• *Systole: contraction (1st sound heard)Lub
• *Diastole: relaxation (2nd sound heard) Dub
The Vascular System
• Consists of arteries,
capillaries, and veins
• Arteries and veins
transport blood
between the capillaries
and the heart
• Capillaries exchange
materials between
blood and tissues
Arteries
• *Carry blood away from
heart
• Blood is high in O2
(oxygenated)
• Highest blood pressure
• Function as– collectors
• Arterioles = small
arteries
• *Coronary arteries
provide blood supply
to the myocardial
cells
Main Arteries
Temporal
Popliteal
Dorsalis
Pedis
Veins
• *Carry blood back to heart
• Blood is low in oxygen
(deoxygenated), high in
CO2
• Function as– distributors
• Venules = small veins
• Inner layer of veins is
smooth but at intervals
there are valves to prevent
the backflow of blood
Capillaries
• Carry blood from arterioles to
venules
• Site of exchange of materials
between blood and tissue fluids
surrounding cells
• Gases (O2 and CO2) move by
diffusion
• Nutrients move by filtration
• 2 way traffic – nourishment and
exchange of wastes
• *Walls are 1 cell thick,
extensions of lining of arteries
and veins
Distribution and Collection Routes
• Distribution:
• Heart to arteries to arterioles to
capillaries
• Distributes oxygen and nutrients
• Exchange occurs in capillaries
• Capillaries carry blood from
arterioles to venules
• Collection:
• Capillaries to venules to veins to
heart
• Transports deoxygenated blood
to heart
• Then, blood is sent to the lungs
for oxygen
Pathways of Circulation
• 2 major pathways of
circulation:
• Pulmonary circulation
• Systemic circulation
Pulmonary Circulation
• Right-sided heart pump
• Superior and Inferior Vena Cava return deoxygenated blood back to the heart into the right
atrium
• Blood passes from right atrium into the right ventricle going through the tricuspid valve
• Right ventricle pumps deoxygenated blood into the pulmonary artery which branches into
the right and left pulmonary arteries, one going to each lung
• Pulmonary arteries are low in oxygen, high in carbon dioxide
• Carbon dioxide will be exchanged for oxygen in the lungs and returned back to the heart via
the pulmonary veins
Systemic Circulation
• Left-sided heart pump
• Pulmonary veins return
oxygenated blood back to the
heart and into the left atrium
• Blood passes through the mitral
valve to the left ventricle
• Left ventricle pumps oxygenated
blood into the aorta (passes
through the aortic semilunar
valve) and out the body
Hepatic Portal Circulation
• Subdivision of Systemic
Circulation
• Blood from abdominal digestive
organs and spleen circulate
through the liver before returning
to the heart
• Veins from the spleen, stomach,
pancreas, intestines do not drain
into the inferior vena cava; they
send their blood to the liver via
the portal vein. Liver is a
manufacturing plant.
• Blood leaves the liver via the
hepatic vein and then empties
into the inferior vena cava; which
goes to the right atrium of the
heart
Cerebral Circulation
• Part of the Systemic
Circulation
• Blood supplied to brain via 2
internal carotid arteries and
2 vertebral arteries. Jugular
veins drain back to the
superior vena cava.
• Brain requires a constant
flow of blood to supply
oxygen and remove wastes.
Blood flow to the brain
doesn’t change with activity.
• Circle of Willis (cerebral
arterial circle) provides for a
continuous blood supply
Renal Circulation
• Part of Systemic
Circulation
• Renal circulation
• Renal arteries bring blood
to kidneys
• Renal veins drain blood
from kidneys
The Lymphatic System
• Functions:
• Returns lymph fluid to
blood
• Filters injurious agents
and prevents them
from entering the
bloodstream
• *Forms some WBCs
(lymphocytes and
monocytes)
• Defends against
infection
Lymph
• Name for tissue fluid
(watery-like) that
enters lymph
capillaries
• Filtration in capillaries
creates tissue fluid,
most is returned to
the blood
Lymphatic Ducts
• 2 ducts empty lymph
into circulatory
system
• Thoracic duct
• *Largest duct
• *Drains ¾ of body and
empties lymph into left
subclavian vein
• Right Lymphatic duct
• Drains about ¼ of body
and empties lymph
into right subclavian
vein
• Flaps in both subclavian
veins permit entry of lymph
but prevent blood from
flowing into lymph vessels
Lymph Nodes and Nodules
• Masses of lymphatic tissue
• Found in groups along
pathway of lymph vessels
• All located at junctions of
head and extremities with
trunk of body
• Functions:
• Filtration
• Phagocytosis
• WBC formation
Lymph Nodes
• *Cervical lymph nodes
• *Tonsils = lymphatic
nodules of pharynx
• *Axilla = armpit
• Iliac=inner hip
• Inguinal=groin
Spleen
• *Located LUQ of abdominal
cavity, just below diaphragm,
behind the stomach
• Functions:
• *WBC production
• *Defense = contains plasma
cells that produce antibodies
• Not considered a vital organ