Topic 12 Cardiovascular System

What does the CV contain, transport, protection?

Contain: Heart, blood vessels, blood

Transport: Gases, nutrients, hormones, wastes , heat

Protects: Disease, fluid loss (clotting)

Where is the heart located

in a cavity called the mediastinum

=Space between lungs within thoracic cavity

What is the pericardium

Double wall sac surrounding the heart

What is the first layers of the pericardium? with examples

a) Fibrous pericardium

-Outermost layer =dense irregular CT

-Anchors to surrounding structures

Example: diaphragm, great vessels (aorta, vena cava etc)

What is the second layer of the pericardium?

b) Serous Pericardium

What are the 2 parts of the serous pericardium?

i. Parietal pericardium ( 2 layers -epithelial & CT)

-Connected to fibrous pericardium

ii. Visceral pericardium (=epicardium) (2 layers epithelial & CT)

-Fused to heart surface and heart wall

-Between pericardial layers= pericardial cavity with serous fluid (lubricates)

What are the 3 parts of the heart

a)Epicardium (visceral pericardium)

-Simple squa epithelium +CT

b)Myocardium

-cardiac muscle

-arranged in spiral/ circualr pattern reinforced with CT

c)Endocardium

-simple squamous epithelium +CT

-Epithelium named endothelium (lines inner surface of heart +All blood vessels)

What is the right atrium

3 major veins connected to right atrium that carry deoxygenated blood into the chamber

What are the 3 major veins?

1.)Inferior vena cava

(carries blood from body below heart)

2.)Superior vena cava

(carries blood from body above heart)

3.)Coronary sinus

(carries blood from the myocardium)

What is the left atrium?

4 veins carry oxygenated blood into the left atrium from the lungs

1.) left pulmonary veins

2.) Right pulmonary veins

What is the right ventricle?

-Pulmonary trunk

-divides to form 2 pulmonary arteries (left and right)

-Carry deoxygenated blood towards the lungs

What is the left ventricle?

-Aorta

-Exits the left ventricle and carries oxygenated blood to all organ systems

Which side of the heart contains oxygenated blood

Lef

What is the Septa (separate chambers)?

a) interatrial septum

-separates atria

b)Interventricular septum

-Separates venricles

What is the Cardiac (Fibrous Skeleton)?

-Fibrous CT separating atria & ventricles

-Provides firm attachment point for cardiac muscles

-Forms solid rings around heart valves, base of aorta and pulmonary trunk that provide structural support

-provides electrical insulation

-Prevents simultaneous contraction of chambers

What are the AV vavles? (For one way flow of blood)

i)Bicuspid (mitral)

-between left atrium & left ventricle

-2 sheet like cusps composed of CT

ii) Tricuspid

-Between right atrium and right ventricle

-3 sheet-like cusps composed of CT

What is the chordae tendineae?

-Strings of CT

-Attach AV cusps to papillary muscles (projections of myocardium)

-Prevents eversion of cusps

What is the semilunar valves? what are the 2 types

-3 cup like cusps each

1) Aortic

-Separates left ventricle + aorta

2)Pulmonary

-Separates right ventricle +pulmonary trunk

What are the 2 cell types in Cardiac Muscle Cells

i) Contractile cells

ii) Conduction system cells

What does it mean when the cardiac muscle cell is modified/ specialized ?

-Conduction system

-Generates electrical signals

-Conduction

What does it mean when the cardiac muscle cell is “Normal”

-Myocardium

-Contraction

What are contractile cells? (Cardiac Muscle Cells)

-Forms majority of myocardium

-Similar to skeletal muscle

How are contractile cells similar to skeletal muscle cells?

a) Striated (myofibrils with sarcomeres)

b) Has sarcoplasmic reticulum & T-tubules

How are contractile cells different from skeletal muscle ?

a) Branched (myofibrils with sarcomeres)

b) Has a single nucleus

c) intercalated discs

=region where 2 fibers meet

d) contain anchoring and gap junctions

What does the conduction system cells do / contain (Cardiac Muscle cells)

-Forms remainder of myocardium

-Cardiac muscle cells modified to produce and conduct electrical impulses

-DO NOT CONTRACT

-Have many gap junctions that help electrical signals to spread fast

What are the parts of the Conduction system cells?

a) SA node

-In R atrium at base of superior vena cava

-Generates impulses the fastest (sets pace)

(pacemaker)

b) AV node

-Base of right atrium

c) Atrioventricular Bundle

-Superior part of interventricular septum

-Electrically connects atria to ventricles

d) AV bundle branches

-Carry impulse to bottom tip of heart

e) Purkinje fibers

-Terminal fibers in ventricles only that carry signals from bottom tip of the heart upward to all parts of the ventricle

True or false? Electrical signals spread from the conduction system to contractile cardiac cells then they contract

True

What is the structure of blood vessels (except capillaries)?

*Tunica means cover*

1) Tunica externa (CT)

-Outside of the blood vessel

2) Tunica media

-Smooth muscle

-elastic fibers (CT)

3) Tunica intima/ interna

-Endothelium (simple squamous epithelium)

-Continuous with endocardium

4)Lumen

-Contains blood (not a layer)

What do blood vessels do?

-Follow path from heart and back to heart

What do arteries do?

Carry blood away from heart ( does NOT refer to oxy or deoxy)

What are the 2 types of arteries?

a) elastic arteries

-large conducting arteries exiting the heart

-Elastic CT in all 3 layers

-Largest arteries (near heart)

e.g. aorta

b)muscular arteries

-smaller distributing arteries

-A LOT OF SMOOTH MUSCLE

-Most amount of arteries

e.g. coronary artery

What are arterioles?

-Little arteries

-Regulate blood flow + blood pressure

What are capillaries?

-ONLY tunica intima- endothelium

-(one cell layer) + basement membrane

-Allows exchange of gases + nutrients

-Gaps allow limited fluid + solutes to leak out

=interstitial fluid (ISF)

What do capillaries form when they unite together?

Venules

What are venules?

-Collect blood from capillaries

-Intima (endothelium) with thin media/externa layers

What are veins?

-Carry blood into heart (does not refer to oxy or deoxy)

-Large lumen

-One way valves prevent backflow of blood

-Thin media (more CT but less smooth muscle than arteries)

What is the overall structure from heart to heart/

Heart

|

Elastic arteries

|

Muscular arteries

|

Arterioles

|

Capillaries

|

Venules

|

Veins

|

Heart

What are the circulatory routes?

-Closed, double circulation

CLOSED= blood confined to heart + blood vessels

DOUBLE = 2 routes (pulmonary + systemic)

What does adult circulation do / contain?

a) Pulmonary circulations

b) Systemic Circulation

What are pulmonary circulation?

-For oxygenation of blood

-Right ventricle to lungs via pulmonary arteries (deoxy blood)

-Pick up oxygen in lungs via capillaries

-Lungs to left atria via pulmonary veins (oxygenated blood)

What is the pulmonary circulation structure/ route ?

Right ventricle

|

Pulmonary arteries

|

Capillaries in respiratory portion of lungs

|

Pulmonary veins

|

Left Atrium

What is systemic Circulation?

-Delivers oxy blood to tissues

-Left ventricle to organs via aorta (oxygenated)

-Organs take up oxygen via capillaries

-Organs to right atrium via superior + inferior vena cava (deoxy)

What is the overall route of systemic circulation?

-Left ventricle to right atrium

What are the subdivides/ sub routes of systemic circulation?

1) cerebral (brain)

2) hepatic (liver)

3) Coronary (heart)

What is the coronary circulation route on the right side (visible externally)?

Left ventricle

|

Aorta

|

Right coronary artery

|

Posterior interventricular artery

|

Marginal artery

What is the coronary circulation route on the left side

Left ventricle

|

Aorta

|

Left coronary artery

|

Anterior interventricular artery

|

Circumflex artery

What do the right and the left side of the coronary circulation make?

1.) Arterioles

2.) Capillaries in myocardium

3.) Venules

4.) cardiac veins

5.) coronary sinus (a blood vessel)

6.) Right atrium

What is fetus circulation?

-Fetus gets O2, nutrients

-Expels wastes to mothers blood

-Exchange site in the placenta (blood supplies close together, but do not mix)

VERY RELIANT ON THE MOTHER

What is the difference from adult circulation to fetal circulations? (fetal circulations)

a) umbilical vein (towards the fetal heart)

-Carries oxy blood from placenta to vena cava

b) Lungs + liver basically non- functional (handled by maternal organs)

c) Umbilical arteries 9away from fetal heart)

-Returns mixed blood to placenta

What is the first shunts to bypass lungs and liver. (Although some blood flow to these organs for nourishment/ growth) #1 DUCTUS VENOSUS

*Venosus means going toward the fetal heart*

1) Ductus venosus

-Connects umbilical vein (oxy blood) to inferior vena cava (deoxy blood) to bypass liver

-Allow most of the oxy blood coming from the placenta to bypass the liver

-Oxy and deoxy blood mixes

-Mixed blood enters fetal atrium via inferior vena cava

What is the second shunts to bypass lungs and liver #2 FORAMEN OVALE

-Hole in interatrial septum

-Allows blood to move from R. to L. atrium (bypass fetal lungs)

What is the third shunt to bypass lungs and liver #3 DUCTUS ARTERIOSUS

-Connects pulmonary trunk + aorta (bypass fetal lungs)

What are the blood CT characteristics ?

-Higher viscosity than H2O

-pH 7.35 - 7.45

• 4 to 6 L in a adult

What is the compositions of BLOOD (CT)?

1.) Plasma (matrix)

-55-60% of blood vol

-Fluid portion with solutes

2.) Formed elements

-40 to 45% of blood vol

-cellular portion

What is plasma (matrix) made out of ?

-Blood minus formed elements

a) H20 =90%

b) Proteins =8%

B.1 ALBUMINS (most plentiful plasma protein)

-Carries hormones, enzymes, medicines throught body

-Control tissue water balance

B.2 FIBRINOGEN (clot formation)

B.3 GLOBULIN (antibodies immunity)

-Detect and bind foreign invaders (bacteria, viruses etc)

c) Other solutes =2%

-Nutrients

-Vitamins

-Wastes

-Electrolytes

-Blood gases -O2 & CO2

What are RBC -erythrocytes / look like (formed elements)?

Hematocrit

=Percentage of blood volume that is made up of RBCS made up of RBCS (usually around 45%)

Anucleate

=Lacks nucleus and other organelles when mature

LOOKS: like a biconcave disc shape

LIFESPAN: 120 days (old cells destroyed in the liver and spleen)

What do RBC -erythrocytes contain?

Hemoglobin

-iron containing pigment protein)

What gives hemoglobin that iron-containing pigment protein?

1.) 4 globin chains (proteins)

2.) 4 iron- containing heme groups (gives blood red colour)

-1 iron per heme

-Sites of reversible O2 binding

What is WBC -Leukocytes / details?

-Nucleated

-Life span varies (days to years )

-Defend against disease

What are the 2 types of Leukocytes?

1) Granulocytes

2) Agranulocytes

What are granulocytes?

-Contains visible protein granules

What do granulocytes include in Leukocytes?

1) Neutrophils (60%)

-All phagocytic (engulf and ingest invaders)

-Kill bacteria

2.) Eosinophils (3%)

-Attack parasites (e.g. worms)

3.) Basophils (1%)

-Release histamine (increase in inflammation)

-Release heparin (decrease in local clotting)

What is Agranulocytes in Leukocytes

-Lack visible protein granules

What does Agranulocytes include in Leukocytes?

1) Lymphocytes (35%)

-immunity

-Contains 2 types

2) Monocytes (5%)

-Enter tissue +enlarge to become macrophages (big eaters)

What are the 2 types of Lymphocytes?

1.) T Lymphocytes

-Activate immune response

-Kill infected/ diseased cells directly

2.) B Lymphocytes

-Become plasma cells

-Release antibodies that circulate in plasma

What are platelets?

-Fragments of cells called megakaryocytes

-Involved in clotting

-Life span: 10 days if not used for clotting

What is Hemopoiesis/ Hematopoiesis?

-Formation of blood cells

-All blood cells arise indirectly from hemocytoblast cells

=stem cells in red bone marrow

What is red marrow in adults?

-Axial skeleton

-Pelvic + pectoral girdles

-Proximal ends of humerus and femur

What is atrial septal defect?

-A hole in the interatrial septum

-Most common type occurs due to incomplete closure of the foramen ovale

What is atherosclerosis?

• Build-up of fat deposits in the tunica intima that leads to narrowing or blockage of arteries