The Heart pt. 1

Question 1

Location of the heart

Answer 1

middle of the thoracic cavity in the mediastinum

Question 2

the mediastinum is the space between the two lungs and is bounded by ……

Answer 2

by the thoracic inlet cranially
by the sternum ventrally
by the spinal column dorsally

Question 3

beside the heart, what other things are found in the mediastinum

Answer 3

blood vessels, thoracic portion of the trachea, thymus gland (young animals), lymph nodes, and nerves

Question 4

the heart has a rounded cranial end called the ____

Answer 4

base of the heart

Question 5

the more pointed caudal end of the heart is called the

Answer 5

apex of the heart

Question 6

the heart doesn’t sit straight along the median plane in the animal. the base is shifted __________ and the apex is shifted __________

Answer 6

the base is shifted to the right nd faces more dorsally
the apex is shifted to the left and sits more ventrally

Question 7

the heart is contained in a fibrous sac called

Answer 7

the pericardium

Question 8

the pericardium is divided into two parts

Answer 8

the fibrous sac is called the pericardial sac
the other portion is called the serous pericardium

Question 9

the pericardial sac is a little loose. why?

Answer 9

so the heart can beat inside
however, it is not elastic so it cannot stretch if the heart becomes abnormally enlarged

Question 10

the serous membrane consists of two other membranes

Answer 10

the smooth, moist serous membrane is called the parietal layer
the other moist serous membrane is called the visceral layer

Question 11

what does the parietal layer of the serous membrane line?

Answer 11

lines the pericardial sac

Question 12

where does the visceral layer of the serous pericardium lie

Answer 12

lies directly in the surface of the heart

Question 13

The space in between the two serous membranes is known as the

Answer 13

pericardial space

Question 14

the pericardial space is filled with ______ which helps prevent ____

Answer 14

filled with pericardial fluid
prevents friction as the layers rub together when the heart contracts

Question 15

The middle and thickest layer of the heart, which is also the muscular layer is called

Answer 15

the myocardium - made of cardiac muscle

Question 16

Remember that the muscle fibers of the heart are jointed side-to-side by multiple branches and end-to-end by intercalated discs. These two features mean that myocardium is made up of _____

Answer 16

continuous muscle sheets that wrap around the chambers of the heart. These sheets make a greater force of contraction possible

Question 17

what are two other advantageous traits of cardiac muscle

Answer 17

it is autorhythmic and it doesn’t fatigue

Question 18

what does autorhythmic mean?

Answer 18

without an outside stimulus, it can start beating in a steady rhythm before an animal is born and continue beating throughout its life

Question 19

The _______ is the outermost layer of the heart wall. It’s a membrane that lies on the external surface of the myocardium.

Answer 19

epicardium
another name for this layer is the visceral layer of the serous pericardium

Question 20

the ______ is the membrane that lies on the internal surface of the myocardium

Answer 20

endocadium

Question 21

what is endocardium composed of?

Answer 21

thin, flat, simple squamous epithelium which forms the lining of the heart chambers. Also covers the valves that separate the chambers of the heart

Question 22

The endocardium is continuous with ______

Answer 22

The endothelium that lines blood vessels

Question 23

the inside of the endocardium is not smooth. it has ridges and nipplelike projections called _____

Answer 23

papillary muscles

Question 24

there are four chamber in the heart

Answer 24

2 atria
2 ventricles

Question 25

the atria does what

Answer 25

receive blood into the heart and forms the base of the heart

Question 26

the ventricles does what

Answer 26

pump blood out of the heart sits underneath the atria wall of the left ventricle forms the apex of the heart

Question 27

left atrium and right atrium are separated by the

Answer 27

interatrial septum is a continuation of the myocardium

Question 28

Atria receives blood from large veins that carry blood to the heart. One filled with blood, then what happens

Answer 28

the wall (myocardium) contract and force blood through one-way valves into the ventricles

Question 29

the atria is identified on the outside of the heart by _______

Answer 29

the auricles are blind pouches that come off the main part of the atria and look like earflaps is part of the atrium, but not the entire atrium

Question 30

why is the myocardium of an atrium not very thick.

Answer 30

Only has to contract enough to move blood to the ventricle

Question 31

left and right ventricles are separated by _____

Answer 31

the interventricular septum a continuation of the interatrial septum

Question 32

the interventricular septum and the interatrial spetum together from the ______

Answer 32

atrioventricular septum

Question 33

interventricular septum is visible on the outside of the heart as the

Answer 33

Interventricular groove the groove contains coronary vessels and if frequently filled with fat

Question 34

what happens when the ventricles have filled with blood from the atria

Answer 34

ventricular walls contract and force blood through one-way valves into arteries

Question 35

right ventricle ->

Answer 35

pulmonary circulation through the pulmonary artery

Question 36

left ventricle ->

Answer 36

systemic circulation through the aorta

Question 37

since the right ventricle doesn't have to pump blood far, the wall are

Answer 37

thinner than that of the left ventricle

Question 38

the left ventricular walls have to pump blood through the entire body, so these walls have to be ....

Answer 38

thicker so it will contract with greater force these walls are so thick they push the right ventricular wall to the right and form the apex of the heart

Question 39

there are 4 one-way valves that control blood flow. where are they located

Answer 39

two are located btwn the right and left atria and respective ventricles the other two are located btwn the ventricles and the arteries they pump blood to these valves close at specific times to prevent backflow of blood to the previous chamber

Question 40

________________ are located between the atria and ventricles

Answer 40

Atrioventricular (AV) valves

Question 41

The right AV valve consists of 3 flaps or cusps of endothelium and is known as

Answer 41

the tricuspid valve

Question 42

the tricuspid valve opens when

Answer 42

the pressure from the amount of blood in the right atrium forces it to open this allows the blood to flow into the right ventricle

Question 43

when does the tricuspid valve close

Answer 43

when the pressure in the right ventricle exceeds the pressure in the atrium and causes the tricuspid valves to snap shut

Question 44

What keeps the valve from opening backwards into the atrium?

Answer 44

a bundle of collagen fiber cords called cordae tendonae attached to the edge of each cusps and to papillary muscles in the wall of the right ventricle

Question 45

the left AV valve only has two cusps and is known as the

Answer 45

bicuspid valve more commonly known as the mitral valve also has cordae tendonae attached

Question 46

the valves that control blood flow out of the ventricles and into the arteries are ________

Answer 46

semilunar valves has three cusps and resemble a crescent moon

Question 47

The right semilunar valve is the _________

Answer 47

pulmonary valve flows to the pulmonary valve also known as the pulmonic valve

Question 48

the left semilunar valve is the ______

Answer 48

aortic valve controls blood flow to the aorta

Question 49

"Skeleton" of the heart is located between the atria and the ventricles made up of 4 dense fibrous connect tissue rings and has 4 functions

Answer 49

separates the atria and ventricles anchors the heart valve provides a point if attachment for the myocardium provides some electrical insulation between the atria and ventricles