Lecture 16 and 17 Flashcards
Describe the characteristics of the heart
generates blood pressure through alternate cycles of the heart wall’s contraction and relaxation.
• Blood flow through the heart is unidirectional because of four
valves within the heart
Describe pulmonary circulation
right side of the heart and the pulmonary arteries and veins;
conveys blood to the lungs and back to the left side of the heart
Describe systemic circulation
left side of the heart and arteries and veins; conveys blood to most body tissues and back to the right side of the heart
Describe the position of the heart
Slightly left of midline deep
to the sternum in a compartment of the thorax known as the mediastinum
More positions of the heart info
The posterosuperior surface of the heart is mainly the left
atrium and is called the base of the heart.
• The superior border is formed by the great arterial vessels
and the superior vena cava.
• The inferior conical end is called the apex.
• The inferior border is formed by the right ventricle.
Describe structure of the pericardum
a tough sack that encloses the heart
composed of fibrous pericardium, serous pericardium
Describe fibrous pericardium
outer covering of tough, dense
connective tissue
Describe serous pericardium
parietal layer
visceral layer
describe parietal layer
lines the inner surface of the fibrous pericardium
describe visceral layer
covers the outer surface of the heart
Function of pericardium
• Restricts heart movements
so that it moves only slightly
within the thorax
What are the 3 layers of the heart wall
Epicardium
Myocardium
Endocardium
Describe Epicardium
consists of the visceral layer of the serous pericardium and areolar connective tissue
Describe Myocardium
—cardiac muscle; thickest of the three layers
Describe endocardium
internal surface of the heart chambers and external surface of the heart valves; consists of the inner heart lining, endothelium and areolar connective tissue.
Descirbe the externals of the heart
• Composed of four hollow chambers - two smaller and superior atria - two larger inferior ventricles
Describe the internals of the heart(Chambers)
The heart possesses four chambers: • Right atrium • Right ventricle • Left atrium • Left ventricle
Describe the internals of the heart(Valves)
The heart also possesses four valves: • Right atrioventricular (tricuspid) • Pulmonary semilunar • Left atrioventricular (bicuspid or mitral) • Aortic semilunar
Describe right coronary artery
Branches into two arteries:
• Marginal artery
• Posterior interventricular artery
Describe marginal artery
supplies the right border of the heart
Describe Posterior interventricular artery
supplies the posterior surface of the left
and right ventricles
Describe left coronary artery
Branches into two arteries:
Anterior interventricular artery
Circumflex artery
Describe Anterior interventricular artery
also called the left anterior descending
artery, supplies the anterior surface of both ventricles and most of the
interventricular septum
Describe Circumflex artery
supplies the left atrium and ventricle
Describe coronary veins
Great cardiac vein
Middle cardiac vein
Small cardiac vein
Describe Great cardiac vein
runs alongside the anterior interventricular artery
Describe Middle cardiac vein
runs alongside the posterior interventricular artery
Describe Small cardiac vein
travels close to the marginal artery
Describe coronary circulation
The right and left coronary arteries travel within the coronary sulcus and supply the heart wall muscle with oxygen and
nutrients.
Describe arteries
. very thick walls
. carry blood from the heart to the organs
. no valves
. carries oxygenated blood away from the heart to the organs
Describe capillaries
. thin walls
. carry blood between veins and arteries
. carries both deoxygenated and oxygenated blood
Describe veins
. thin walls
. carries deoxygenated blood towards the heart from the organs to the heart
. has valves
Describe diastole blood pressure
Relaxation of the heart
During relaxation, the myocardium in each chamber relaxes and the
chamber fills with blood
Describe systole blood pressure
Contraction of the heart
During contraction, the myocardium forces blood from either the
• atria to ventricles
• ventricles to major blood vessels (pulmonary artery/aorta)
Describe how the different types of vessel interconnect to transport blood
Capillaries connect the arteries to veins
Arteries deliver the oxygenated blood to the capillaries
Exchange of oxygen and carbon dioxide occurs
Capillaries deliver the deoxygenated blood to the veins for transport back to the lungs and heart
Describe systemic circulation step 1
Oxygenated blood flows from the left atrium to the left ventricle and then is pumped into the aorta
Describe systemic circulation step 2
Blood passes from the aorta into elastic arteries and then into muscular arteries before entering arterioles
Describe systemic circulation step 3
Blood in arterioles enters systemic capillaries for the exchange of gases and nutrients
Describe systemic circulation step 4
Deoxygenated blood exits capillary beds into venules and then into veins
Describe systemic circulation step 5
Deoxygenated blood is conducted to either the superior or inferior vena cava and then enters the right atrium of the heart
Describe pulmonary circulation step 6
Blood flows from the right atrium to the right ventricle and is then pumped into the pulmonary trunk
Describe pulmonary circulation step 7
The pulmonary trunk conducts deoxygenated blood into pulmonary arteries to the lungs
Describe pulmonary circulation step 8
The blood passes through the smaller arteries before entering pulmonary capillaries for gas exchange
Describe pulmonary circulation step 9
Oxygenated blood exits the lung via a series of progressively larger veins that merge to form the pulmonary veins
Describe pulmonary circulation step 10
Pulmonary veins drain into the left atrium
Describe pulmonary circulation step 11
The cycle repeats
Describe postnatal circulation patterns step 1
. The umbilical cord is clamped and the baby no longer receives oxygen and nutrients from the mother
Describe postnatal circulation patterns step 2
Lungs expand within first breaths of air, ductus arteriosus and foramen ovale both close
Describe postnatal circulation patterns step 3
Babys circulation and blood flow through the heart now functions like an adults
Describe fetal circulation patterns step 1
Oxygenated blood enter from right side of heart and flows into right atrium
Most of blood flow across to the left atrium through forearm ovale
Describe fetal circulation patterns step 2
From left atrium blood moves into left ventricle
then pumped into the ascending aorta
Describe fetal circulation patterns step 3
From aorta, oxygenated blood sent to brain and to heart muscle
Blood is also sent to lower body
Describe fetal circulation patterns step 4
Blood returning to the heart from the fetal body contains carbon dioxide and waste products as it enters the right atrium
flows down into the right ventricle, then bypasses the lungs and flows through the ductus arteriosus into the descending aorta
Describe fetal circulation(blood flow) 1
Oxygen and nutrients from the mother’s blood are transferred across the placenta to the fetus through the umbilical cord.
Describe fetal circulation(blood flow) 2
This enriched blood flows through the umbilical vein toward the baby’s liver. There it moves through a shunt called the ductus venosus
Describe fetal circulation(blood flow) 3
This allows some of the blood to go to the liver. But most of this highly oxygenated blood flows to a large vessel called the inferior vena cava and then into the right atrium of the heart.
Describe fetal circulation patterns step 5
connects to the umbilical arteries. From there, blood flows back into the placenta
the carbon dioxide and waste products are released into the mother’s circulatory system
Describe fetal circulation patterns step 6
Oxygen and nutrients from the mother’s blood are transferred across the placenta
Then the cycle starts again.
