Print Options

Card layout: ?

← Back to notecard set|Easy Notecards home page

Instructions for Side by Side Printing
  1. Print the notecards
  2. Fold each page in half along the solid vertical line
  3. Cut out the notecards by cutting along each horizontal dotted line
  4. Optional: Glue, tape or staple the ends of each notecard together
  1. Verify Front of pages is selected for Viewing and print the front of the notecards
  2. Select Back of pages for Viewing and print the back of the notecards
    NOTE: Since the back of the pages are printed in reverse order (last page is printed first), keep the pages in the same order as they were after Step 1. Also, be sure to feed the pages in the same direction as you did in Step 1.
  3. Cut out the notecards by cutting along each horizontal and vertical dotted line
To print: Ctrl+PPrint as a list

70 notecards = 18 pages (4 cards per page)

Viewing:

Human A&P exam 2

front 1

Introduction

back 1

  • The heart – a muscular double pump with two circuits:

–Pulmonary circuit— takes blood to and from the lungs

–Systemic circuit—vessels transport blood to and from body tissues

  • Atria (‘entranceway’)— receive blood from the pulmonary and systemic circuits
  • ventricles (‘hollow belly’)—the pumping chambers pumps blood around the two circuits

front 2

The Heart...

back 2

  • Heart pumps blood through 120,000 km (75,000 miles) of blood vessels (BVs)

–Beats 100,000 times/day or 35 million times/year

–Pumps 5 liters of blood/minute

front 3

Pulmonary and Systemic Circuits

back 3

  • Pulmonary Circuit:

–Right side receives oxygen-poor blood from the body tissues

–Pumps this blood to the lungs

–Picks up oxygen and dispels CO2

  • Systemic Circuit:

–Left side receives oxygen-rich blood returning from the lungs

–Pumps this blood throughout the body

–Supplies O2 and nutrients to the body tissues

front 4

Location and Orientation within the Thorax

back 4

  • Heart: hollow and cone-shaped

–About the size of your fist

  • Largest organ of the mediastinum (central compartment of the thoracic cavity)

–Located between the lungs

–Apex lies to the left of the midline

–Base is the broad posterior surface

front 5

Pericardium of the Heart—Coverings

back 5

  • Pericardium—triple-layered sac that encloses the heart
  • Two primary layers

–fibrous pericardium: strong layer of dense connective tissue

–Serous pericardium: formed from two layers

  • parietal layer of the serous pericardium
  • Visceral layer of the serous pericardium
  • Pericardial cavity – between the primary layers

–Epithelial cells secrete lubricating serous fluid that reduces friction

front 6

Three Layers of the Heart Wall

back 6

  • Epicardium
  • Myocardium
  • endocardium

front 7

Epicardium:

back 7

  • outer layer of heart wall (and inner visceral layer of serous pericardium)

–Thin, transparent layer

front 8

Myocardium:

back 8

  • middle layer of heart wall

–Cardiac muscle, responsible for pumping action

front 9

Endocardium:

back 9

  • innermost, thin layer of heart wall

–Simple squamous epithelium

–Lines inside of the myocardium

–Covers heart valves and tendons attached to the valves

–Continuous with the epithelial lining of large blood vessels

front 10

Layers of the Pericardium and of the Heart Wall

back 10

front 11

Arrangements of Cardiac Muscle Bundles

back 11

  • Myocardium organized in crisscrossing bundles
  • Function to squeeze blood through the heart in the proper directions

front 12

Heart Chambers

back 12

  • Right and left atria – superior chambers
  • Right and left ventricles – inferior chambers
  • Internal divisions – interventricular and interatrial septa

front 13

External Markings

back 13

–Coronary sulcus forms a crown encircling a boundary between atria and ventricles

–Anterior interventricular sulcus

front 14

Right Atrium

back 14

  • Forms right border of heart: receives oxygen-poor blood returning from systemic circuit via veins

–Superior and inferior vena cava and coronary sinus

front 15

Right Ventricle

back 15

  • Receives blood from right atrium through the tricuspid valve or right atrioventricular (AV) valve
  • Pumps blood into pulmonary circuit via pulmonary trunk

front 16

  • Internal walls of right ventricle

back 16

–Chordae tendineae: bands attached to cusps of right tricuspid valve

–papillary muscles: attached to chordae tendineae

front 17

Pulmonary semilunar valve:

back 17

  • located at opening of right ventricle and pulmonary trunk

front 18

Left Atrium

back 18

  • Makes up heart’s posterior surface: receives oxygen-rich blood returning from lungs

-Through two right and two left pulmonary veins

  • Opens into the left ventricle through the bicuspid or mitral valve (aka the left atrioventricular valve)

front 19

Left Ventricle

back 19

  • Forms apex of the heart
  • Internal walls of left ventricle

–Chordae tendineae: attached to cusps of left mitral valve

–Papillary muscles

  • Superiorly opens into the aorta

–Pumps blood through systemic circuit via aortic semilunar valve (aortic valve)

front 20

Heart Valves—Valve Structure

back 20

  • Paired atrioventricular (AV) and semilunar valves enforce one-way flow of blood through the heart

–Designed to prevent back flow in response to pressure changes in the heart chambers

  • Each valve

–Two or three cusps

front 21

Heart Valves—Valve Structure

back 21

  • Atrioventricular (AV) valves lie between atria and ventricles

–Right tricuspid valve (3 cusps)

–left bicuspid valve (2 cusps)

  • Aortic and pulmonary (semilunar) valves lie at the junction of the ventricles and great arteries

–3 cusps

front 22

Heart Valves

back 22

front 23

Function of the Atrioventricular (AV) Valves

back 23

(a) AV valves open; atrial pressure greater than ventricular pressure

front 24

Function of the Atrioventricular (AV) Valves

back 24

(a) AV valves open; atrial pressure greater than ventricular pressure

front 25

Function of the Atrioventricular (AV) Valves

back 25

(a) AV valves open; atrial pressure greater than ventricular pressure

  • Ventricles relaxed --> valves forced open by blood pressure exerted on their atrial side

front 26

Function of the Atrioventricular (AV) Valves

back 26

(b) AV valves closed; atrial pressure less than ventricular pressure

front 27

Function of the Atrioventricular (AV) Valves

back 27

(b) AV valves closed; atrial pressure less than ventricular pressure

front 28

Function of the Atrioventricular (AV) Valves

back 28

(b) AV valves closed; atrial pressure less than ventricular pressure

  • Contraction of ventricles force contained blood superiorly --> valves are pushed shut

front 29

Function of the Semilunar Valves

back 29

  • Ventricular contraction

–Valves pushed open

–Cusps flattened against artery walls

front 30

Function of the Semilunar Valves

back 30

  • Ventricular relaxation

–Back flowing blood closes valves

front 31

Pathway of Blood Through the Heart

back 31

  • Beginning with oxygen-poor blood from the superior and inferior venae cavae (coronary sinus)

–Go through pulmonary and systemic circuits

–A drop of blood passes through all structures in sequence

  • Atria contract together
  • ventricles contract together

front 32

Blood flow through the heart.

back 32

front 33

Structure of Heart Wall

back 33

  • Walls differ in thickness

–atria—thin walls

–Ventricles—thick walls

  • left ventricle generates more force and pumps blood at a higher pressure

–Systemic circuit longer than pulmonary circuit

–Offers greater resistanceto blood flow

front 34

Structure of Heart Wall

back 34

  • Left ventricle—
    three times thicker than right

–Exerts more pumping force

–Flattens right ventricle into a crescent shape

front 35

Cardiac Muscle Tissue

back 35

  • Forms a thick layer called myocardium – contains cardiac muscle cells and connective tissue

–Cardiac muscle cells

  • Short, branching, 1 or 2 nuclei
  • Cells joined at intercalated discs (complex junctions)
  • Striated like skeletal muscle

–Contractions

  • Pump blood through the heart and into blood vessels
  • Sliding filament mechanism

front 36

Cardiac Muscle Tissue

back 36

  • Intercalated discs – complex junctions between cardiac muscle cells - form cellular networks

–Adjacent cells interlock through meshing ‘fingers’

–Fasciae adherens

  • Long junctions bind adjacent cells and transmit contractile force

–Gap junctions

  • Allow ions to pass between cells, transmitting contractile signal to adjacent cells

front 37

Blood Supply to the Heart

back 37

  • Heart walls – too thick to obtain oxygen and nutrients from contained blood—heart needs those substances to beat!
  • Functional blood supply – coronary arteries

–Left and right coronary arteries

–Arise from the aorta

–Located in the coronary sulcus

front 38

Blood Supply to the Heart – Coronary Arteries

back 38

front 39

Blood Supply to the Heart

back 39

  • Deoxygenated blood from heart wall

–Into right atrium

–Occupy sulci on the heart surface

  • Coronary sinus – Returns most venous blood from the heart to the right atrium

front 40

Blood Supply to the Heart – Cardiac Veins

back 40

front 41

Blood Vessels

back 41

Delivery system of dynamic structures that begins and ends at heart

  • Arteries

Carry blood away from heart

Oxygenated except for pulmonary circulation & umbilical vessels of fetus

  • Capillaries

Contact tissue cells

Directly serve cellular needs

  • Veins

Carry blood toward heart

Deoxygenated except for pulmonary circulation

front 42

Generalized structure of arteries, veins, and capillaries

back 42

front 43

Structure of Blood Vessels

back 43

Except for the smallest, composed of three layers (tunics)

Innermost -> outermost

  • Tunica intima: Endothelium lines lumen of all vessels

(simple squamous epithelium)

Smooth surface; Continuous with endocardium of heart

“Intimate” contact with blood

  • Tunica intima: sheets of smooth muscle & elastic fibers

Contraction causes vasocontriction (smaller vessel diameter)

Relaxation causes vasodilation (larger vessel diameter)

Influence blood flow and blood pressure

  • Tunica externa—composed of connective tissue

Contains many collagen and elastic fibers

Cells and fibers run longitudinally

Vasa vasorum (vessels to the vessels): tiny arteries, capillaries, veins

front 44

Generalized structure of arteries, veins, and capillaries

back 44

front 45

Types of Arteries

back 45

  • Passage of blood through the arteries:

Elastic arteries --> Muscular arteries --> Arterioles

front 46

The relationship of blood vessels to each other and to lymphatic vessels

back 46

front 47

Types of Arteries

  • Elastic Arteries

back 47

  • elastin in all three tunics
  • Ex. aorta & its major branches
  • Large lumen = low resistance
  • Inactive in vasoconstriction
  • Act as pressure reservoirs—expand and recoil as blood ejected from heart

front 48

Types of Arteries

  • Muscular Arteries

back 48

  • Distal to elastic arteries
  • Deliver blood to body organs
  • thick tunica media with more smooth muscle
  • Active in vasoconstriction

front 49

Types of Arteries

  • Arterioles

back 49

  • smallest type of artery
  • Lead to capillary beds
  • Control flow into capillary beds via vasodilation and vasoconstriction

front 50

Capillaries

back 50

smallest blood vessels – diameter from 8–10 µm

  • A single layer of endothelial cells surrounded by a basement membrane
  • Most important vessels
  • red blood cells pass through single file

Site-specific functions of capillaries

Lungs: oxygen enters blood, carbon dioxide leaves

Small intestines: receive digested nutrients

Endocrine glands: pick up hormones

Kidneys: removal of nitrogenous wastes

front 51

Capillary Permeability

back 51

  • Endothelial cells held together by tight junctions and desmosomes - block passage of small molecules

But junctions are incomplete…

  • Intercellular clefts: gaps of unjoined membrane

Passageway for small molecules to enter and exit

  • Fenestrations (pores): holes through endothelial cells

Increases permeability

front 52

Types of capillaries- based on structure:

back 52

  • Continuous: most common, lack pores

Found in most organs (skeletal muscle, lungs, skin, CNS)

  • Fenestrated: large pores; increasedpermeability

Occur where high exchange rates are needed (kidney, small intestines)

  • Sinusoids: many pors and clefts; most permeable

Occur in limited locations (liver, bone marrow, spleen)

front 53

1.Continuous capillaries

back 53

front 54

1.Fenestrated capillaries

back 54

front 55

1.Sinusoid capillaries (sinusoids)

back 55

front 56

The relationship of blood vessels to each other and to lymphatic vessels.

back 56

front 57

Capillary Beds

back 57

  • Network of capillaries running through most tissues
  • Precapillary sphincters – regulate the flow of blood to tissues

Composed of smooth muscle cells

Regulated by local chemical conditions and vasomotor nerves

front 58

Veins

back 58

Venules: smallest veins

Form when capillaries unite

  • Postcapillary venules: smallest venules
  • Venules join to form veins

Veins

Conduct blood from capillaries toward the heart

  • Range in size from 0.5mm to 3 cm (venae cavae)
  • Blood pressure is much lower than in arteries
  • Walls are thinner
  • lumen of a vein is larger

Capacitance vessels

i.e. blood reservoir

Contain up to 65% of blood supply

Valves

Vascular sinus

front 59

Veins: Adaptations for Blood Flow Return

back 59

Large-diameter lumens offer little resistance

Venous valves prevent backflow of blood

  • Most abundant in veins of limbs

Venous sinus

  • Flattened veins with extremely thin walls
  • E.g., coronary sinus of the heart and dural sinuses of the brain
  • Collect blood

front 60

Circulatory Routes

back 60

Parallel blood flow

Each organ receives its own supply of oxygenated blood

Two basic routes for blood flow:

  • Systemic circulation
  • Pulmonary circulation

front 61

Systemic Circulation

back 61

  • Carries oxygen and nutrients to body tissues
  • Removes carbon dioxide and other wastes and heat from the tissues
  • All systemic arteries branch from the aorta
  • All veins of systemic circulation drain into superior vena cava, inferior vena cava, or coronary sinus
  • The blood vessels are organized according to regions of the body

front 62

Major Arteries

back 62

front 63

Major Veins of the Systemic Circulation

back 63

front 64

Physiology of Circulation

  • Blood flow

back 64

volume of blood flowing through vessel, organ, or entire circulation in given period

  • Measured as ml/min
  • Equivalent to cardiac output (CO) for entire vascular system
  • Relatively constant when at rest
  • varies widely through individual organs, based on needs

front 65

Physiology of Circulation

  • Blood pressure (BP)

back 65

blood pressure per unit area exerted on wall of blood vessel by blood

Measured as millimeters of Mercury (mm Hg)

Pressure gradient: blood moves from higher to lower pressure areas

front 66

Physiology of Circulation

  • resistance

back 66

Opposition to flow; generally in systemic circulation

Measure of amount of friction blood encounters with vessel walls

front 67

Physiology of Circulation

  • Three important sources of resistance

back 67

Constant:

1.Blood viscosity

  • ¨The "stickiness" of blood due to formed elements and plasma proteins; Increased viscosity = increased resistance

2.Total blood vessel length

  • ¨Longer vessel =greater resistance encountered

Variable:

3.Blood vessel diameter

  • ¨Constantly changing; important influence on resistance
  • ¨Smaller vessel diameter, high resistance
  • ¨large vessel diameter, less resistance

front 68

Relationship Between Blood Flow, Blood Pressure, and Resistance

back 68

Blood flow(F) directly proportional to blood pressure gradient (change in P)

  • If change in P increases ­, blood flow ­decreases

Blood flow inversely proportional to resistance (R)

  • If R increases ­, blood flow decreases

Resistance more important in influencing local blood flow

  • Easily changed by altering blood vessel diameter

front 69

Systemic Blood Pressure

back 69

Blood Flow

  • Generated by pumping of heart

Blood flow opposed by resistance -->Pressure

Blood Pressure

  • highest in the aorta and declines throughout the pathway (0 mm Hg in the right atrium)

Arteries close to the heart are flexible and accommodate high volume

front 70

Arterial Blood Pressure

back 70

systolic pressure: pressure exerted in aorta during contraction of left ventricle (systole)

  • Blood is forced into the aorta
  • Averages 120 mm Hg in normal adult

Diastolic pressure: lowest level of aortic pressure

  • When blood is prevented from flowing back into the ventricles by the closed semilunar valve (diastole, relaxing of ventricle)
  • 70–80 mm Hg