Circulatory system
BLOOD- Fluid Connective
Tissue
• Amount of Blood present in the body of
an adult human being –about 5-5.4
liters (a bucketful)
• Structural Organization of Blood:
• The Human Blood is classified into two
major components• a) Cellular
b) fluid
Cellular Components of Blood
RBCs (Erythrocytes)
Properties of RBCs
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Formed in Adults- Red bone Marrow
Life cycle – 120 days
Destroyed-In liver
Mature RBCs in Mammals DO NOT have
Mitochondria, Nucleus, Endoplasmic
Reticulum.
• Contains Pigment Hemoglobin
WBCs (Leucocytes)
Classification of WBCs.
Leucocytes
•
Leucocytes- also called WBCs.
– round, nucleated .
– makes up the body defence system.
Controls immunity by engulfing
pathogens by phagocytosis.
Functions of WBCs
(Phagocytosis)
Blood Platelets (Thrombocytes)
• Thrombocytes- also called
Platelets
These are cells which help in
the process of formation of
blood clot (Thrombus) at the
site of
injury
Blood Clotting
Mechanism of blood clotting
• Ruptured platelets release thromboplastin also
called thrombokinase enzyme.
• Thromboplastin acts upon inactive prothrombin
from ruptures RBCs and converts it into
activated Thrombin, with Vitamin K and calcium
ions acting as co-factors.
• Thrombin acts upon soluble plasma protein
fibrinogen and converts it into an insoluble mesh
work of fibrin.
• The wound is plugged
• A straw coloured liquid oozes out of the clot.
This is called Serum. Serum = Plasma –
Fibrinogen.
BLOOD
• Fluid Components:
• also called plasma
• contains proteins (fibrinogen is to be
mentioned)
• 92% is water. It also contains salts,
dissolved nutrients, hormones, enzymes,
etc
Functions of Blood
Cells are continously adding waste products,
secretions and metabolites to blood
while taking from it vital nutrients,
oxygen, hormones and other
substances.
Overall, blood performs the following
functions:
1.Transports oxygen from the lungs to body
tissues and transports the waste
products of cellular metabolism and
nutrients, hormones and enzymes.
2.Regulates blood clotting, body
temperature, acid-base balance, water
and electrolytes.
3.Protects against harmful organisms
through white cells and antibodies.
CARDIO-VASCULAR SYSTEM
IN HUMAN BEINGS
Anatomy of the Heart
Structure of the Heart
• Location of the heart – Thoracic cavity. (Chest cavity)
• Protection of the heart – Bony – (Rib Cage) and
membranous (pericardium)
• Heart Muscles:
1. The human heart is a muscular pump.
2. Cardiac muscle is also involuntary. So functionally,
cardiac muscle and smooth muscle are similar.
3. Cardiac muscle does have several unique features.
Present in cardiac muscle are intercalated discs, which
are connections between two adjacent cardiac cells.
Intercalated discs help multiple cardiac muscle cells
contract rapidly as a unit. This is important for the heart
to function properly.
Structure of the Heart
• Heart Chambers:
1. There are four chambers in the heart - two
atria and two ventricles. The atria (one is called
an atrium) are responsible for receiving blood
from the veins leading to the heart. When they
contract, they pump blood into the ventricles.
2. The muscle in the walls of the ventricles is
much thicker than the atria as they need to push
blood over a greater distance.
Structure of the Heart
3. Between the atria and the ventricles are
valves, overlapping layers of tissue that allow
blood to flow only in one direction. Valves are
also present between the ventricles and the
vessels leading from it.
4. The right side of the heart contains impure
blood and the left side of the heart contains pure
blood. The four chambers of the heart ensure
that there is no mixing of pure and impure blood.
This structure ensures efficient supply of oxygen
to the body to meet with the high energy
demands.
Cardiac cycle
•
The heart muscles are involuntary and
under the control of a self excitatory
nerve center situated at the roof of the
right auricle called Sino-auricular node.
This node is also called the pace maker
or pace setter
Cardiac cycle
•
The cardiac cycle comprises of three stages:
Auricular systolea) Under the influence of an impulse from
SAN the auricular chambers undergo systole.
b) This causes the impure blood to enter from
Rt. auricle to Rt. Ventricle via the tricuspid
valve and pure blood from the lt. auricle to lt.
ventricle through the Bicuspid or Mitral valve.
c) These valves always open into the
ventricles as their upturning into the auricles is
prevented by chordae tendinae.
Cardiac cycle
• Ventricular systole– During this phase the Auriculo-ventricular node picks
up the impulse from the SAN and sends it down the
bundle of nerves called Bundle of His which divide
into Purkinje fibres.
– The Ventricles contract pushing the blood against the
tricuspid and bicuspid valves which close to prevent
back flow of blood. This generates the first sound of
the heart beat- LUBB
– Pure blood moves into the aorta, while impure blood
enters into the Pulmonary artery through the semilunar valves.
Cardiac cycle
• Joint Diastole
• a) During this phase the auricles are in their
relaxed state, while the ventricles begin to relax.
• b) Due to differential pressure blood tends to
flow back from The Aorta to the left Ventricle and
from the Pulmonary Artery to the right Ventricle
nut is prevented from flowing back as the semilunar valves close –generating the second
sound of the heart beat –DUP
Circulation of Blood
Double Circulation
• During a Cardiac Cycle The blood flows
circulates in two cycles.:
• A) Between Heart and Lungs- Called
Pulmonary Circulation.
• B) Between Heart and the entire body –
Called Systemic Circulation.
Hi!
Just wanted to remind you
that you must NOT forget
to write the two termsSYSTEMIC and
PULMONARY
While describing
DOUBLE CIRCULATION.
• Blood pressure- The ratio of systolic
pressure to diastolic pressure during a
Cardiac Cycle. Its numerical value is 120 /
80 mm of Hg.
• The apparatus used to measure blood
pressure is called Sphygmomanometer.
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Blood Vessels
Artery V/s Veins
• Artery
• Vein
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Always carry blood away from the
heart
Always carry oxygenated blood
except pulmonary artery.
They have thick muscular walls
They have narrow lumen
They dilate and constrict with the
heart beat- This is called pulse
They carry blood under pressure
They are deeply seated in the
body.
•
•
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Always carry blood towards the
heart
Always carry de-oxygenated blood
except pulmonary vein.
They have thin muscular walls
They have broad lumen
They do not dilate and constrict
with the heart beat.
They do not carry blood under
pressure. They have unidirectional valves at regular
intervals.
They are superficially seated in
the body.
Lymphatic vessels
LYMPH
• Lymph is a fluid which is present in the lymphatic
vessels.
• This fluid is primarily the extra tissue fluid which is
returned back into the venal blood.
• It is similar to plasma except that it has a number of
lymphocytes.
• At places the lymph vessels get enlarged to form lymph
nodes which are the store houses of lymphocytes.
• Lymph contains tissue secretions like hormones,
enzymes etc.
Functions of Lymph
• The lymphatic system has three primary
functions. First of all, it returns excess interstitial
fluid to the blood.
• The second function of the lymphatic system is
the absorption of fats and fat-soluble vitamins
from the digestive system and the subsequent
transport of these substances to the venous
circulation.
• The third and probably most well known function
of the lymphatic system is defense against
invading microorganisms and disease.
Transport in Plants
Transport of Food in Plants
Transport of Water and Minerals in
Plants
Ascent of sap• Active uptake of ions from soil into roots
• Endosmosis of water.
• Generation of Root pressure
• Transpiration Pull
• Cohesive –Adhesive Forces
Ascent of sap• Active uptake of Ions- The cells in the roots actively
absorb ions from the soil solution to maintain the inner
solution at a hypertonic level. This ensure that water
always moves from the soil solution (hypotonic)into the
solution inside the roots (Hypertonic)
• Roots pressure – As the water moves from one cell to
the next inside the root hairs and roots there develops a
pressure, due to accumulation of salts at the basal cells
of xylem called root pressure that pushes the water
column into the xylem
Ascent of sap• Root pressure alone cannot push the
water column right up the tall trees.
• Transpiration Pull. – as the wateris lost
from the aerial parts of the trees as
vapour called transpiration there develops
a suction pull that pulls the entire water
column upwards. This is called
Transpiration Pull Theory – proposed by
Jolly and Dixon
Ascent of sap• Cohesion- Tension Theory- According to
this theory there exists a force of attraction
between water molecules (cohesive
forces) and between water molecules and
the walls of the xylem (adhesive forces).
• These forces ensure the continuity of the
water column and help in conduction of
water – Ascent of sap.
Cohesive forces
Adhesive forces
Translocation of Food
• Food is prepared in leaves in plants and
are translocated by the phloem.
The channels of transport are the sieve
tubes. The force required for translocation
is provided by the companion cells.
• Food material move from the region of
manufacture into the phloem by active
process.
Translocation of Food
• After entering the sieve tubes the nutrients
being in high concentration exert an
osmotic pressure which causes the entry
of water into this region.
• A high turgor pressure develops.
• This pressure forces the nutrients to move
towards the region with low turgor
pressure.