Cardiovascular system/ Blood & Heart Flashcards
What are the two main components of blood
Blood is divided into two main components:
* Plasma - the liquid portion of blood which carries cells and cell fragments
* The Formed element/ blood cells
What are the three fromed elements of blood
Erythrocytes (Red Blood Cell)
* Bi concave with
* no Nucleus
* Carry oxeygen bound to heamoglobin and some carbon dioxide
* life span of around 120 days
* Formation of Erythrocytes known as Erythropoiesis and takes 7 days
Leukocytes (White blood cells)
* Active in immunity protecting the body from invading cells and removing debris
* Can be subdivided into Granulocyte and Agranulocyte
Platlets (Thrombocytes)
* Disc shaped cell fragments
* Life Span of 8-11 days
* No nucleus but contain enzymes and Mitochnondria
* Created by Megakraryocytes (Bone marrow cells)
What are the two types of Leukocytes
Granulocytes:
* Neutrophils - Function is Phagocytosis (ingestion of foreign material/bacteria enclosing them in vesicle and secreting digestive enzymes to destroy the foreign body)
* Eosinophils - function is involoved in allergic reaction and defense against parasite
* Basophils - Function Involved in allergic reactions and inflammatory reactions
Agranulocytes: **
Lymphocytes - Funciton is Immunity they perform Phagocytosis (engulfing of foreign matter enclosed in a vesicle and secreting digestive enzyme to destroy the foreign body)
Monocytes - macrophages, largest of all Leukocytes/white blood cells
What is Albumin and why is it importnat
- Albumin is a plasma protein and it helps to maintain osmotic pressure
- Lack of albumin will cause a drop in osmotic pressure water will not be drawn into the capillary, instead it will remain in the interstitual spaces intrun causing oedema
- It also is a carrier for fatty acids, some drugs and steroids.
What is meant by the term haematopoesis
Haematopoesis referes to the process of blood cell formation
How does the shape of Erythrocytes enable it to exchange gases and move through the blood vessles
- The biconcave shape provides a larger surface area which allows for a more rapid gaseous exchange.
- The central portion is thinner allowing for ease of movement across a
smaller area. - The biconcave shape also allows it to bend more easily when it moves through blood vessels.
Where are most plasma proteins synthesised
The liver
Explain the proccess of the destruction of Erythrocytes (Red Blood Cells)
- At the end of their 120 day life span they are broken-
down in the spleen, liver and bone marrow by
macrophages
What are the three layers of the heart
Endocardium - Thin, Smooth inner layer of the of epithelial cells which line the hearts interior providing a smooth surface for blood to travel through the heart
Myocardium - The heart muscle, the thickest layer which pumps blood through the vessels
Epicardium - a serous fluid membrane forms thin outermost layer of the heart wall and reduces friction between the heart and pericardium (sac which encloses the heart)
Describe the path of blood flow through the heart
Deoxygenated Right Atrium - Through Tricuspid Valve - Right Ventricle - Pulmonary Semilunar Valve - Pulmonary Artery (to the lungs to receive oxeygen)
Oxygenated Blood recieves oxeygen and travels back to the heart through the Pulmonary Veins - Left Atrium - Mitral Bicuspid Valve - Left Ventricle - Aortic Semi Lunar Valve - Aorta - Aortic Arch (Upper body tissue cappilaries) - or Desending Aorta (lower body tissue cappilaries) blood give 02 and recieves c02
Blood Returns Through the Superior Vena Cava (upper body) - or Inferior Vena Cava (lower body) to Right Atrium
Label the heart
What is the Conduction system of the heart
This basically refers to the cells that initiate and distribute stimulus for the heart to contract. The conduction system consists of the following parts:
* The Sinoatrial Node
* The Atrioventricular Node
* Conducting cells = AV Bundle and Purkinje fibres
Describe the Impulse conduction through the heart
SA Node (Sinoatrial) located in the Right Atrium is the pacemaker of the heart. It sends an electrical impulse (Posotive Charge Depolarization) through the Atrial Myocardium to the AV Node (Atrioventricular) 100 msec pause to allow for atrial contraction before the ventricles do.
AV Node sends the Posotive charge through fibres known as the bundle of HIs.
Branches of this Bundle of His branch throughout the heart muscles and are known as Purkinje fibres.
The Purkinje fibres conduct the impulse and distribute it to the Ventricular myocardium muscles and Ventricualr contraction begins.
Draw and expplain EKG of the heart conduction system
P wave - Small wave - Depolarization of the atria (Atrial Contraction)
QRS Complex - Large Peak - Depolarization of the Ventricle Ventricle Contraction (Signal is strong because the ventricle muscle is larger than atrial)
T wave - Ventricle Repolarization
Note Atrial repolarization is not shown on EKG becuase it happens at the same time as Ventricular Depolarization so is hidden behind the QRS Complex Wave
Explain the Cardiac cycle and events that take place during it
Cardiac cycle = The period between the start of a heartbeat and the begining of the next heartbeat.
It contains alternating periods of contraction and relaxation.
Can be divided into 2 phases Systole and Diastole
Explain the phases of the Cardiac Cycle
