MHS1002- Human Structure and Function (Week 7-12)

Clinsci year 1- session 1

Heart- Mediastinum

• Space that holds heart

• Between lung

What is the position of the heart (in mediastinum) compared to diaphram?

• Sits on top

What is the position of the heart (in mediastinum) compared to Sternum?

• Sits posteriorly to sternum

What is the position of the heart (in mediastinum) compared to the midline

• 1/3rd on the right of midline

• 2/3rds on the left of midline

Where is the Base of the heart located?

• positioned posterior and slightyl up

• Anterior to thoracic spine

Where is the Apex of the heart?

• points anteriorly to the left and inferiorly

Heart- Pericardium

• membranous sac that encloses the heart

Pericardium- What are the two layers?

• Fibrous

• serous

Pericardium- What are the two layers of serous membrane

• Parietal (outer)

• visceral (inner)

Pericardium- What is the Pericardial cavity

• space between parietal and visceral membrane

• Filled with pericardium fluid

Heart wall- three layers?

• epicardium (outer)

• myocardium (Middle)

• endocardium (Inner)

Heart Wall- What layer of the heart is made up from the pericardium?

• Epicardium

1 and 8- Right Atrium

2 and 10- Right Ventricle

3- Apex

4- Left ventricle

5- Anterior interventricular sulcus

6- Coronary sulcus

7-Left Atrium

9- Posterior interventricular sulcus

Heart- Anterior/posterior interventricular sulcus

• separates left and right ventricle

Heart- Coronary sulcus

• Like a crown

• Separates atrium and ventricles

Heart Vessels- Superior/inferior vena cava

• Deoxygenate blood arrives in right atrium through vena cava from body

Heart vessels- Pulmonary trunk/artery

• Divides into right and left for lungs

• sends deoxygenated blood from right ventricle to lungs

Heart Vessels- Pulmonary Veins

• bring oxygenated blood from lungs to Left Atrium

• One left and right

Heart Vessels- Aorta

• sends oxygenated blood from left ventricle to body

Vessels delivering blood TO the heart are called:

Veins

Vessels delivering blood FROM the heart are called:

Arteries

Heart Chambers- Right atrioventricular opening

• Tricupsid valce

• opening between Left Atrium and left ventricle

Heart Chambers- Left atrioventricular opening

• Bicuspid / mitral valve

• Opening between left Atrium and left Ventricle

Heart Chamber- Papillary muscle

• 3 in Right ventricle, 2 in left ventricle

• Contract and pulls Chordae Tendinae to open and close atrioventricular opening

Heart Chamber- Chordae Tendinae

• Connects atrioventricular opening to papillary muscles

Heart Chamber- Interventricular septum

• divides the ventricles

Heart Chamber- Aortic semilunar valve

• valve between left ventricle and aorta

Heart Chamber- Pulmonary semilunar valve

• valve between right ventricle and pulmonary trunk

What chamber of the myocardium is the thickest?

• Left Ventricle because it pumps blood to the entire body

Cardiac Cycle- Atrial Diastole (Phase 1)

• Heart is relaxed

• blood flows from atria to ventricle

• Atrioventricular valve Opens

Cardiac Cycle- Atrial Systole (phase 2)

• Only Atria contract to fill ventricle

• Atrioventricular valve Opens

Cardiac Cycle- Isovolumetric Contraction

• Atria relaxes

• Blood flow makes AV close

• no valve opens

Cardiac Cycle- Ventricle systole

• ventricle contracts, blood leaves heart

• Semilunar valve opens

Cardiac Cycle- isovolumetric relaxation

• heart is relaxed

• blood flow closes semilunar valve

• no valve open

Blood Vessels- Coronary sinus

• vein that drains blood from heart into right atrium

Blood Vessels- coronary arteries

• supply heart with blood

Pulmonary system

• Cricut where deoxygenated blood leaves the heart, to the lungs, then back to the left atrium

Systemic Circuit

• Circuit of blood that goes from the heart, to the body, then back to the heart

Blood vessels- What are the three layers (Tunics) of blood vessel walls

• Tunica intima (innermost)

• Tunic media

• Tunic externa

4 diffrences between arteries and veins

Arteries:

• thicker walls

• more elastic (to accommodate for pressure)

• Smaller lumens (round shaped)

Veins:

• Thinner walls

• Have valves to prevent blood flowback

Veins- Vanous valve

Large veins have valves to prevent flowback

Veins- Muscular pump

• muscular muscle contract to push blood

Veins- Respiratory pump

• during inhaling, pressure in thoracic increases, which increases blood pressure in veins

Veins- Vasoconstriction

• decreases blood vessel room = increased blood pressure

Blood vessels- Capillaries

• exchange center

• connects arterioles to venules

Blood vessels- What kind of muscle tissue is in blood vessels?

• smooth muscles

• involuntary

• regulated by autonomic nervous system

• Tunica intima (BOTH)

• Endothelium(BOTH)

• subendothelial layer (BOTH)

• Internal elastic membrane (Artery)

• Tunica media (BOTH)

• External elastic membrane (artery)

• Tunica externa (BOTH)

• vasa vasorum (BOTH)

Blood vessels- Ascending, arch, decending

• 3 main parts of aorta

• Ascending → arch → descending

Aortic Arch- Brachiocephalic Trunk

• divides into right common carotid and right subclavian

Aortic arch- Left common carotid artery

• supplies blood to head / neck

• divides into external and internal carotid arteries

Branches of Aortic arch- Left subclavian artery

• Supplies upper limbs

• extends into axillary artery

Branches of Aorta- Common iliac arteries

• divide into internal and external iliac

• supply pelvis and lower limbs

Arteries of upper limb

subclavian → axillary → brachial → Radial / ulnar artery

Artery of lower limbs

• external iliac → femoral artery → popliteal artery → anterior / posterior tibial artery

Systemic Veins- superior vena cava