SILVERTHORN
CHAPTER 14 – CARDIOVASCULAR PHYSIOLOGY
OVERVIEW OF THE CARDIOVASCULAR SYSTEM
The cardiovascular system is a series of tubes (blood vessels) filled with fluid (blood) connected
to a pump (the heart). Pressure generated in the heart propels blood through the system. The
primary function of the cardiovascular system is the transportation of materials to and from all
parts of the body. The cardiovascular system consists of the heart, blood vessels (arteries &
veins) and blood.
The heart is divided by a central wall, called septum, into left and right halves. Each half functions
as an independent pump that consists of an atrium and a ventricle. Well-oxygenated blood is
bright red, and low-oxygen blood is darker red. From the right side of the heart, blood is pumped
into the pulmonary arteries and enters the capillaries in the lungs, where gas-exchange will take
place. The blood then travels to the pulmonary veins, eventually reaching the left side of the heart.
Types of circulation
1. Pulmonary circulation: consists of pulmonary arteries, veins and the capillaries of the lungs.
2. Systemic circulation: blood is pumped into the aorta, and enter the right side of the heart
via the superior and inferior vena cava.
3. Coronary circulation: circulation that is responsible for blood supply to the heart itself via
coronary arteries, veins and the coronary sinus.
Portal systems
1. Blood supply to the digestive tract and liver. Two capillary beds of the digestive tract and
liver, joined by the hepatic portal vein, are an example of a portal system.
2. Blood supply to the kidneys: two capillary beds are connected in series.
3. Blood supply to the hypothalamic-hypophyseal portal system, which connects the
hypothalamus and the anterior pituitary.
PRESSURE, VOLUME, FLOW AND RESISTANCE
Liquids and gases, including blood flow down pressure gradients from region of higher pressure
to regions of lower pressure. The heart creates the highest pressure when it contracts, causing
blood to flow into the blood vessels. As blood moves through the system, pressure is lost because
of friction between fluid and the blood vessel walls. Blood pressure falls as blood moves farther
from the heart. From high to low pressure: Heart, Aorta, arties, arterioles, capillaries, venules,
veins and venae cavae.
– Pressure in a fluid: the force exerted by the fluid on its container. Flow is directly
proportional to the pressure gradient. The higher the pressure gradient, the grater the fluid
flow
o Hydrostatic pressure: pressure that occurs, while fluid is not moving.
o Driving pressure: pressure created in the ventricles: contraction causes high
pressure blood. This principle might also occur during dilation or contraction of the
blood vessels.
Silverthorn – chapter 14: Cardiovascular physiology Page 1 of 14
CHAPTER 14 – CARDIOVASCULAR PHYSIOLOGY
OVERVIEW OF THE CARDIOVASCULAR SYSTEM
The cardiovascular system is a series of tubes (blood vessels) filled with fluid (blood) connected
to a pump (the heart). Pressure generated in the heart propels blood through the system. The
primary function of the cardiovascular system is the transportation of materials to and from all
parts of the body. The cardiovascular system consists of the heart, blood vessels (arteries &
veins) and blood.
The heart is divided by a central wall, called septum, into left and right halves. Each half functions
as an independent pump that consists of an atrium and a ventricle. Well-oxygenated blood is
bright red, and low-oxygen blood is darker red. From the right side of the heart, blood is pumped
into the pulmonary arteries and enters the capillaries in the lungs, where gas-exchange will take
place. The blood then travels to the pulmonary veins, eventually reaching the left side of the heart.
Types of circulation
1. Pulmonary circulation: consists of pulmonary arteries, veins and the capillaries of the lungs.
2. Systemic circulation: blood is pumped into the aorta, and enter the right side of the heart
via the superior and inferior vena cava.
3. Coronary circulation: circulation that is responsible for blood supply to the heart itself via
coronary arteries, veins and the coronary sinus.
Portal systems
1. Blood supply to the digestive tract and liver. Two capillary beds of the digestive tract and
liver, joined by the hepatic portal vein, are an example of a portal system.
2. Blood supply to the kidneys: two capillary beds are connected in series.
3. Blood supply to the hypothalamic-hypophyseal portal system, which connects the
hypothalamus and the anterior pituitary.
PRESSURE, VOLUME, FLOW AND RESISTANCE
Liquids and gases, including blood flow down pressure gradients from region of higher pressure
to regions of lower pressure. The heart creates the highest pressure when it contracts, causing
blood to flow into the blood vessels. As blood moves through the system, pressure is lost because
of friction between fluid and the blood vessel walls. Blood pressure falls as blood moves farther
from the heart. From high to low pressure: Heart, Aorta, arties, arterioles, capillaries, venules,
veins and venae cavae.
– Pressure in a fluid: the force exerted by the fluid on its container. Flow is directly
proportional to the pressure gradient. The higher the pressure gradient, the grater the fluid
flow
o Hydrostatic pressure: pressure that occurs, while fluid is not moving.
o Driving pressure: pressure created in the ventricles: contraction causes high
pressure blood. This principle might also occur during dilation or contraction of the
blood vessels.
Silverthorn – chapter 14: Cardiovascular physiology Page 1 of 14
