Transport in Human Body
- It’s the process of transporting blood, and lymph,
through different blood vessels, so the process of
transport depends on:
A- Circulatory system.
B- Lymphatic system.
A- The circulatory system consists of:
1- The heart. 2- Arteries. 3- Veins.
4- Blood capillaries. 5- Blood.
The heart:
Comparison between Arteries and Veins:
Comparison: Arteries Veins
Picture:
Type of blood: - Oxygenated blood, - Deoxygenated blood,
except pulmonary except pulmonary vein
artery which comes which comes out the
out of the heart and two lungs and goes to
goes to the two the heart.
lungs.
Outer layer: Connective tissue. Connective tissue.
Middle layer: Thick (Pulsate) Less thick (don’t pulsate)
Inner layer: - Epithelial cells - Epithelial cells, and
with elastic fibers. there’s valves to direct
the blood without back
flowing.
Location: - Buried among the - Near to the skin
body muscles. surface.
Diameter: - Relatively smaller - Relatively wider than
than that of the that of the artery.
vein.
Blood capillaries:
- It’s the connection of the tiny microscopic vessels,
which branches from arteries and veins, and the
microscopic vessel that branch from the arteries is
called arteriole, and the one that is branched from the
veins is called venule.
The blood :
- It’s the fluid that is being transported through the
circulatory system, and it consists of many contents,
as the following :
A- Plasma. B- RBCs C- WBCs D- Platelets.
Properties of blood
Color: pH: Volume:
Red viscous fluid. 7.4 (Weak alkaline). About 5-6 liters of blood.
- A sample of blood from regular human body,
contains plasma with a percentage of 55%, and the
45% contains WBCs, RBCs, and blood platelets,
Also plasma contains proteins (like: Albumin,
Globulin, Fibrinogen, and Prothrombin) with a
percentage of 7% of the whole volume of the plasma,
and 91% of it is water, and 2% of it is hormones,
antibodies, Enzymes, wastes (Urea), and the
remaining 1% contains inorganic salts [like: Na⁺,
Ca²⁺, Cl- , (HCO₃)¯ ], as the following diagram:
Comparison between RBCs, WBCs, and platelets:
Comparison RBCs WBCs Platelets
Shape Biconcave Don’t have specific Non-cellular small
round shaped cells. shape. sized particles.
Number/ Male: Average volume is About 250,000 cells.
mm³ 4.35 - 5.65 million. 7000 cells and increase
Female: in case of infection.
3.92 – 5.13 million.
Age 120 days. Some types live for 13: About 10 days.
20 days.
Color Red. Colorless --
Presence of Enucleated Nucleated --
nucleus
Function - Transport O₂ - Protect the body - Play an
from the lungs through: important role
to all body 1- Attack microbes. in the blood
parts. 2- Get rid of dead cells. clotting process
- Transport CO₂ 3- Produce antibodies. after injuries.
from all body
parts to the
lungs.
Site of Bone marrow Bone marrow/Spleen/ Bone marrow
formation Lymphatic system
Hemoglobin:
- Hemoglobin is a protein found in red blood cells that
is responsible for carrying oxygen from the lungs to
the rest of the body. It also helps to carry carbon
dioxide from the body's tissues back to the lungs, as
the following diagram:
Blood clot process:
- Blood clotting is the process that helps stop bleeding
when a blood vessel is injured, in which when a
blood vessel is cut or damaged, platelets (tiny cell
fragments) rush to the site, platelets stick together to
form a temporary plug over the injury, special
proteins in the blood called clotting factors work
together to create a mesh-like network called fibrin.
This fibrin network traps more platelets and blood
cells, forming a solid clot, as in the following
diagram:
Mechanism of heart beat (pumping blood):
- The heartbeat is a rhythmic contraction and
relaxation of the heart muscle, which pumps blood
throughout the body. This rhythmic action is
orchestrated by an electrical system within the heart
itself, through the following procedures:
1- Electrical Impulse Generation:
- Sino-atrial (S.A node): This cluster of cells in the right
atrium is often called the "pacemaker" of the heart. It
spontaneously generates electrical impulses at a regular
rate.
2- Electrical Signal Propagation:
- The electrical impulse from the SA node spreads across
the atria, causing them to contract and push blood into the
ventricles.
- The impulse then reaches the atrio-ventricular (A.V
node), located in the wall between the atria and ventricles.
- The A.V node slightly delays the signal, allowing the
ventricles to fill completely before they contract.
- The impulse then travels down the bundle of His and
through the Purkinje fibers, which rapidly distribute the
signal to the ventricular muscle.
3- Cardiac Muscle Contraction:
- The electrical signals cause the heart muscle to
contract in a coordinated manner.
- First, the atria contract, pushing blood into the
ventricles.
- Then, the ventricles contract forcefully, pumping
blood out of the heart:
- The right ventricle pumps blood to the lungs for
oxygenation.
- The left ventricle pumps blood to the rest of the body.
Types of blood circulations:
- There three major types of blood circulations, which
are:
1- Pulmonary circulation:
- It’s the process of transporting blood from the heart
(right ventricle) to the two lungs through the
pulmonary artery, to oxygenate the blood, then the
blood is transported to the heart again through the
pulmonary veins, then poured in the left ventricle.
Path: Right ventricle -> Pulmonary artery -> Lungs ->
Pulmonary vein -> Left ventricle.
2- Systemic circulation:
- It’s the process of transporting blood from the heart
(left ventricle) to all body parts (cells) through the
aorta, to enrich all body cells with oxygen gas and
nutrients and carry out the wastes, then the blood is
deoxygenated, then the blood is transported to the
heart again through the all body vessels, then poured
in the right ventricle, to restart the whole cycle.
Path: Left ventricle -> Aorta -> Body tissues -> Veins ->
Vena cava -> Right ventricle.
3- Hepatic portal circulation:
- It’s the process of transporting blood from the small
intestine to liver through the hepatic portal vein, and
the blood is being filtered in the liver from nutrients,
and stored in the liver in the form of glycogen, and
then the remaining blood is transported to heart
through two vessels, which are hepatic vein and then
to inferior vena cava, and then poured in the right
ventricle.
Path: Small intestine -> Hepatic portal vein -> Liver ->
Hepatic vein -> Inferior Vena cava -> Right ventricle.
B- Lymphatic system:
- It‘s a vital part of your immune system, playing a
crucial role in defending your body against infection
and disease, it’s a network of vessels, nodes, and
organs that circulate a fluid called lymph throughout
the body, and works closely with the circulatory
system, but it's a separate system with distinct
functions.
- The lymphatic system consists of :
1- Lymphatic routes:
- Similar to blood vessels, these tubes carry lymph
throughout the body.
2- Lymphatic nodes:
- Small, bean-shaped structures located throughout the
body (neck, armpits, and groin).
- They filter lymph, trapping bacteria, viruses, and
other harmful substances.
3- Lymph:
- It’s a clear, colorless fluid that circulates through the
lymphatic vessels. It contains:
- White blood cells (lymphocytes) that fight infection.
- Proteins. - Cellular debris. – Fats.
