Cardiovascular System

• keeps blood in motion

• beats about 100,000 times per day

• pumps about 1.5 million gallons of blood per year

• about 3 gallons per minute

• has 4 chambers

Heart

• contains nutrients and oxygen

• collects waste

blood

Where is the heart located?

Mediastinum

Heart pumps blood into two circuits

Pulmonary circuit, systemic circuit

• depleted of oxygen

• to/from the lungs

• blood returning from the body

• enters the right side of the heart

• in the lungs oxygen gets added to the lungs

  • carbon dioxide gets removed

• goes back to the heart and out the aorta

Pulmonary circuit

• left side of heart

• pumps blood to the body with oxygen

systemic circuit

Once blood leaves the heart into blood vessels

• transport blood away from the heart’

• most contain oxygenated blood that is ready to nourish cells

arteries

Once blood leaves the heart into blood vessels

• transports blood toward the heart

veins

Once blood leaves the heart into blood vessels

• interconnects arteries & veins

• allow nutrients & waste transfer between body cells & blood

capillaries

• heart is surrounded by the ______

  • consists of two parts

    • outer fibrous ______

    • inner serous ______

pericardium

Consists of two parts

• inner visceral layer = epicardium

  • attached to the surface of the heart

• outer parietal layer = adjacent to the fibrous pericardium

• Space between the layers is called the pericardial cavity & contains pericardial fluid

Serous pericardium

Walls of the heart consist of 3 layers

Epicardium, Myocardium, Endocardium

Wall of the heart

• Outer layer of the heart

• AKA the visceral layer

• made up of connective tissue & has blood vessels

Epicardium

Wall of the heart

• Middle layer

• consist of cardiac tissue, including cardiac muscle cells

  • connective tissue, blood vessels & nerves

Myocardium

Wall of the heart

• internal layer, endothelial surface

• lining the inside of the chambers of heart

• connective tissue

• thinnest

Endocardium

Cardiac muscle Tissue

• striated appearance

Sarcomeres

• Branched morphology (shape)

• Dependent on aerobic respiration to make energy

  • oxygen required

  • lots of mitochondria & myoglobin

• has many blood vessels to nourish it

• muscle cells contract without info coming from the CNS

• cardiac muscle cells are tightly interconnected

  • intercalated discs

Cardiac Muscle tissue

• Only have one nucleus

• Branch shape

• need lots of oxygen

  • a lot of mitochondria

• contracts by itself without the NS (involuntary)

Cardiac muscle cells

• cell to cell junctions

• binds the myofibrils of the cells together

  • Desmosomes

    • proteins that hold two cardiac muscle fibers together

    • really strong

• gap junctions to allow cells to communicate directly → allow heart muscle cells to send action potentials without neurotransmitters

Intercalated discs

• helps keep the heart its shape

• mostly made up of connective tissue

• every cardiac cells is wrapped in an elastic sheath & fibrous sheet

• helps prevent overexpansion

• helps spread out forces of contractions

cardiac skeleton

Heart has 4 chambers

• Two _____

  • left and right

  • have muscle around them & when contract they push blood into the second set

• Two _____

  • left and right

atria, ventricles

• superior border of the heart

• where the heart vessels enter and leave (connect together)

base

• inferior/ bottom part of the heart

• ventricles come to a point

apex

• consist of the:

  • right atrium

  • right ventricle

  • left ventricle

anterior surface

• consist of the:

  • left atrium and a small portion of the right atrium

posterior surface

• left and right regions

• positioned at the base of heart

• both have thinner walls

• both contain an expandable anterior portion called an auricle

atria

• left and right regions

• positioned at the apex of the heart

• both have thicker walls

  • left is thicker than right (more cardiac muscle)

ventricles

the left and right atria are separated by?

interatrial septum

left and right ventricles is separated by?

interventricular septum

What separates the atria and the ventricles

atrioventricular valves

• receives blood depleted of oxygen via the Superior vena cava, inferior vena cava, and coronary sinus

  • vena cavae bring blood from body back to heart

  • coronary sinus enters posterior side of the right atrium

right atrium

• receives oxygen-poor blood

• blood enters the right ventricle by passing thru the right atrioventricular valve aka tricuspid valve

• blood leaves by passing thru the pulmonary valve (pulmonary semilunar valve)

• leads to the pulmonary trunk then to the right & left pulmonary arteries

Right ventricle

This right valve has three flaps/cusps & 3 papillary muscles

• connected to papillary muscles (smooth muscle) & chordae tendineae (cords that…)

  • prevent valve inversion when ventricles contract

tricuspid valve

• receives oxygenated blood from lungs via right & left pulmonary veins

• blood passes thru left atrioventricular valve

  • mitral valve/left AV valve

left atrium

Which veins are the only ones that carry oxygenated blood

right and left pulmonary veins

• largest chamber in the heart & has the thickest (myocardium) wall

• needed for strong contractions to pump blood thru entire circuit/ all of our blood pressure

• it also has chordae tendineae connecting yo 2 cusps & 2 papillary muscles

left ventricle

When blood leaves the left ventricle which valve does it pass through?

• AKA aortic semilunar valve

• first blood enters the ascending _____

• then travels to the _____ arch & down the ascending ___ & to all body parts

aortic valve

• thinner wall

• weaker contraction

right ventricle

• thicker wall

• powerful contraction

left ventricle

• Heart gets oxygen from this

• supply blood to

• the cardiac muscle via _____

• right and left _____ arteries

• drain cardiac venous blood from lungs & into right atrium

coronary circulation

• made up of arteries & veins that transport blood between the heart & the lungs

• to add oxygen and remove waste/ co2

• travels short distances

• blood pressure is lower

• walls of the arteries are thinner → less smooth muscle

pulmonary circuit

• made up of arteries & veins that transport oxygenated blood between the heart & al other tissues

• often travels longer distances

• blood pressure is higher

• walls of the arteries are thicker → more smooth muscle

systemic circuit

vessels that interconnect arteries and veins

capillaries

contain 30-35% of the blood volume

arteries and capillaries

contain 65-70% of the blood volume

veins

Blood vessels that act as blood reservoirs (storage)

• more elastic/stretchy

vein

The walls of the blood vessels (except capillaries) consists of 3 layer (tunics)

• give tremendous strength 💪

• wall are thick & even contain their own blood vessels

intima, media, externa

• deepest layer

• endothelium

tunica intima

• middle layer

• smooth muscle

• involved in vasoconstriction (walls contract and lumen gets smaller) & vasodilation (walls relax and lumen widens)

tunica media

• superficial layer

• AKA adventitia

• fibers (collagen/connective tissue) of this wall anchor the blood vessels

tunica externa

• inside blood vessel

• where blood flows

lumen

• large vessels up to 2.5 cm in diameter

• contain elastic connective tissues in media & intima

• tolerate pressure changes during cardiac cycle

• can store pressure

  • ex:

    • aorta

    • brachiocephalic trunk

    • pulmonary trunk

elastic arteries