Lecture 10: Cardiovascular System Flashcards
Where is the heart located?
In the mediastinum cavity ⅔ to the left of the midline.
Identify the main surfaces of the heart:
Base (Posterior Surface)
Apex (Left Corner)
Anterior Surface
Inferior Surface (diaphragmatic surface)
Identify and elaborate the components of the heart wall.
- Epicardium; Most external, thin, made out of mesothelium and CT acts as the visceral serous layer
- Myocardium; Middle Layer, very thick, thickness determines how hard the chamber will work.
- Endocardium; Thin most inner layer made of endothelium and CT
Outline the flow of deoxygenated blood throughout body:
Deoxygenated blood comes from superior and inferior vena cava and coronary vein.
→ Enters the right atrium → Passes through to right ventricle (via tricuspid valve) → Right ventricle pumps blood towards the pulmonary trunk through the pulmonary semilunar valve to be directed into the lungs. → Blood coming from lungs enter the pulmonary veins which enter the left atrium. → Pumps blood via bicuspid valve into thick left ventricle→ Pumps blood through the aortic semilunar valve into the ascending aorta which is distributed throughout body
What are the pouches on the anterior surface of the heart called and what is there role.
Auricles: Allow L+R atrium to hold larger volume of blood by increasing capacity
How does the heart have its own blood supply?
Heart wall contains grooves known as sulci which allow blood vessels to lie in and supply blood to the heart
- Coronary Sulci: btw atria and ventricles
- Anterior and Posterior interventricular sulci
What veins drains the upper body, lower body, and heart wall respectively?
Superior Vena Cava, Inferior Vena Cava, coronary sinus
What separates the L + R atria and what is the feature that is grown over after further development of the heart.
Interatrial septum:
Fossa Ovales → Originally the foramen ovales which bypassed the non functioning heart during foetal development.
What are the ridges or the atrial wall called and where do they come from?
Musculi Pectinati; derived from embryonic development.
What is the right atrioventricular valve called and what is its function?
Tricuspid Valve; stops reguritation of blood from ventricle back into atrium.
What is the role of the right ventricle?
Pumps blood into the pulmonary artery towards the lungs for oxygenation via the pulmonary semilunar valve
What are the main features inside the right ventricle:
Inner muscular ridges: Trabeculae carnal
Papillary muscles x 3 → Attached to chordae tendineae EACH control the tricuspid valve through contractions
What makes up the base of the heart?
Left atrium
What are the main features of the left atrium?
- Thicker myocardium wall
- Receives oxygenated blood from lungs via 4 pulmonary veins on the posterior surface.
- Passes into ventricle via BICUSPID VALVE
Still has musculi pectinati ridges.
What are the main features of the left ventricle?
- THICKEST MYOCARDIUM OF ALL CHAMBERS;
- 2x papillary muscles and chordae tendinae
- Trabeculae Carnae
*
Identify the circled area and its original function
Ligamentum Arteriosum → ORIGINALLY Ductus Arteriosum which bypassed pulmonary circulation during foetal development.
Identify regions of the fibrous skeleton
QUESTION MARK TOP → BOTTOM = Left Trigone, Right Trigone conus tendon
Surrounding valves: 1. Right Atrioventricular ring 2. Left Atrioventricular ring 3. Pulmonary fibrous ring 4. Aortic fibrous ring
What part of the nervous system runs the cardiac conduction system? What are the terms used for contraction and relaxation respectively.
Autonomic Nervous System: In charge of strength and timing on contraction DO NOT MAKE RHYTHM,.
Systole = Contraction Diastole: Relaxation
Outline the node pathway for heart contraction.
- Activated by sinoatrial node (begins self excited nerve impulses_
- Atrioventricular node (Opens Valve)
- Atrioventricular Bundle (Closes valve)
- Left and right bundle branches (Prep Ventricle walls)
- Purkinje Fibers (Ventricles contract to send blood throughout body)
Identify the blood vessels and their direction of the distribution of blood:
Arteries: Blood to Body
Veins: Blood to heart
Capillaries: Where gas exchange occurs
Identify the blood vessels and their direction of the distribution of blood:
Arteries: Blood to Body
Veins: Blood to heart
Capillaries: Where gas exchange occurs
Identify the 3 layers of basic vessels and their features:
- Tunica Intima: Innermost layer of thin endothelium. (Internal elastic lamina in arteries only)
- Tunica Media: Medium layer of smooth elastic tissue. (external elastic lamina in arteries only)
- Tunica Externa: External connective tissue which houses the blood supply and autonomic nerves.
What is an anastamose?
Union or joining of blood vessels.
What are the 3 subcategories of arteries and what are they determined by.
- Elastic Arteries (conducting x large) Bigger diameter of smooth muscle in tunica media
- Muscular arteries (Distributing x medium) Relatively smaller diameter of smooth muscle
- Arterioles (resistance x small)
Describe the composition of an elastic artery
>1 cm in diameter
Tunica intima quite thick
Tunica media relatively thick (hold shape of artery)
Tunica externa relatively thin layer
Eg: Aorta or Pulmonary Trunk
Describe the composition of muscular arteries
Tunica intima relatively thinner than tunica media which has thinner external elastic lamina. Tunica external thicker than media.
Eg Brachial Artery
Describe the composition of the arterioles:
10 -100 micrometres in diameter
Unlikely to have internal elastic lamina ; tunica intima
Tunica media VERY THINK
Tunica Externa underdeveloped poorly defined CT
Define capillaries and their subcategories. Highlight each of their function
Connection btw the venules and the arterioles, where nutrients are exchanged freely
→ Continuous, has pinocytotic vesicles
→ Fenestrated, Allows molecular exchange.
Outline the composition of Venules:
Often run with arterioles.
Tunica intima; endothelium + Basement membrane
Tunica Media: none to 2 layers of smooth muscle
Tunica Externa: none to limited layers of poorly defined CT
Outline the composition of veins:
Large Lumen; Contains thinner walls than arteries due to the absence of external and internal elastic lamina.
Tunica intima: CT rich in elastic fibres and may contain valves
Tunica externa: CT rich in collagen and elastic fibres thicker than tunica intima
What is the skeletal muscle pump and what is its function?
Aids in the venous return of blood from the limbs. Works via the contraction of skeletal muscles on veins. These contraction provide increased pressure which open proximal valves for blood flow and closes distal valve as to avoid regurgitation of blood backwards.
Briefly describe the aorta and parts.
The aorta is a very large artery of 2-3 cm in diameter
- Ascending aorta (Directly from heart upwards)
- Arch Aorta (bend which then projects inferiorly)
- Descending ( becomes thoracic artery at thoracic cavity and and abdominal artery through abdominal cavity_
- Will bifurcate into 2 branches at the pelvic region -L+R common iliac artries.
Briefly describe the aorta and parts.
The aorta is a very large artery of 2-3 cm in diameter
- Ascending aorta (Directly from heart upwards)
- Arch Aorta (bend which then projects inferiorly)
- Descending ( becomes thoracic artery at thoracic cavity and and abdominal artery through abdominal cavity_
- Will bifurcate into 2 branches at the pelvic region -L+R common iliac artries.
Identify all branches within the aorta and what they supply
Ascending: L + R Coronary Artery (Supplies heart wall)
Arch : Brachiocephalic trunk → right subclavian artery and right common carotid artery
Left common carotid artery and left subclavian artery
Abdominal Aorta: terminates at iliac region to form L+R iliac arteries.
What are your principal veins?
Superior vena cava: drains deoxygenated blood from upper body
Inferior vena cava: drain deoxygenated blood from lower body
What are the arteries that make up THE CEREBRAL ARTERIAL CIRCLE
L+R Internal carotid artery
L+R Vertebral artery
What drains the blood from the cephalic region?
Dural Venous sinuses:
Made up of the superior sagittal sinus
Inferior Sagittal sinus
Straight sinus
Transverse L + R sinus
Sigmoid sinus; drains blood into the internal jugular
What are the upper limb arteries:
Subclavian Artery
Axillary Artery
Brachial Artery (bifurcates)
Radial + Ulna arteries
What are the lower limb arteries?
Right and Left Common illiac Artery
Femoral artery
Popliteal (posterior to the knee joint)
Anterior and Posterior Tibial artery
Fibular Artery
What is the role of the coronary arteries? Identify the common ones.
Supply the myocardium of the heart wall.
Left coronary arteries: anterior interventricular artery (wall of ventricles), circumflex artery (left atrium and ventricle)
Right Coronary arteries: posterior interventricular artery( wall of ventricles), marginal artery (Right ventricle)
Identify the main veins that drain the heart wall into the right atrium:
Great Cardiac vein: Drains L+R Ventricle and L atrium
Middle Cardiac vein: Drains L+R ventricle
Small Cardiac vein: Drains R ventricle and R atrium
Anterior Cardiac vein: Drains R ventricle
