1. The Cardiovascular System CHAPTER 14

2. Between 3rd-7th ribs in ___________ animals and 2nd-6th ribs in ___________ animals
Lies in the ________________, which is the space between the right and left lungs.
Trachea, esophagus, and other vascular structures are also found here
When looking at the surface of the heart, the only part of the atria that are visible are the ________________ (ear-shaped portions).
LOCATION OF HEART:

3. Orientation of the heart
_________ of the heart is shifted to the left of the chest and is formed by the left ventricle
_________ - the top of the heart where major blood vessels enter and exit

4. Anatomy of the heart: Chambers
The dorsal chambers of the heart are the left and right ____________.
They receive blood that is returning to the heart. The atria are separated by the __________________________ ______________.
The ventral chambers of the heart are the left and right _____________.
They send blood out of the heart. The ventricles are separated by the __________________________ ______________.
________ ventricle - long and narrow, thick-walled, makes up the apex of heart
________ ventricle - broader surface area, thinner walls
Anatomy of the heart: Chambers

5. -Right Atrioventricular Valve (aka Right AV valve/Tricuspid Valve) has ___ flaps/leaflets
-Left Atrioventricular Valve (aka Left AV Valve/Mitral Valve/Bicuspid Valve) has ___ flaps/leaflets
These valves open and close simultaneously!
The AV valves are attached to _____________ _____________, which prevent the flaps from bending back into the atria.
_______________ muscles connect the chordae tendinae to the interventricular septum
AV VALVES

6. -Aortic valve (found at base of Aorta) -Pulmonary/pulmonic valve (found at base of Pulmonary Trunk) -Both valves are made of ____ leaflets -These valves open and close simultaneously! -They do not have chordae tendinae
SEMILUNAR
VALVES

7. Major vessels that enter and exit the heart
Each chamber of the heart is associated with a major blood vessel. The ATRIA receive blood that is RETURNING to the heart, so they are associated with ______________.
The right atrium receives DEOXYGENATED BLOOD from the BODY via the __________ ___________ (cranial and caudal).
The left atrium receives OXYGENATED BLOOD from the LUNGS via the _______________ ___________ (left and right).

8. Major vessels that enter and exit the heart
Each chamber of the heart is associated with a major blood vessel. The VENTRICLES send blood AWAY from the heart, so they are associated with _____________.
The right ventricle receives DEOXYGENATED BLOOD from the right atrium, and sends it to the LUNGS through the _______________ _________, which continues as the left and right Pulmonary Arteries.
The left ventricle receives OXYGENATED BLOOD from the left atrium, and sends it to the BODY through the ______________, which is the largest and thickest artery in the body.

9. VESSELS Right Atrium = Vena Cavae
Right Ventricle = Pulmonary Trunk/Arteries
Left Atrium = Pulmonary Veins
Left Ventricle = Aorta
Arteries—carry blood ________ from heart
Veins—carry blood _________ heart
artery -> arteriole -> capillary -> venule -> vein
Capillaries are where gas exchange occurs (O2 in and CO2 out at the lung capillaries, O2 out and CO2 in at the systemic capillaries).
VESSELS

10. 1. Caudal/Cranial Vena Cavae 2. Right atrium 3
1. Caudal/Cranial Vena Cavae 2. Right atrium 3. Tricuspid/Right AV Valve 4. Right ventricle 5. Pulmonary/pulmonic valve 6. Pulmonary Trunk/Arteries 7. Lungs – pulmonary circulation (CO2 out, O2 in) 8. Pulmonary Veins 9. Left atrium 10. Mitral Valve/Left AV Valve 11. Left Ventricle 12. Aortic Valve 13. Aorta 14. Systemic circulation (O2 out, CO2 in)
Blood Flow Steps

11. Heart: coronary circulation
The heart has its own blood supply, the coronary circulation.
The left and right coronary arteries originate from the root of the aorta, right behind the aortic valve
Cranial and caudal vena cavae join together with the coronary _________ that collects blood from coronary circulation and returns it to the right atrium

12. THE PERICARDIUM -The sac the covers the heart
-The pericardium consists of an outer fibrous pericardium and an inner serous pericardium.
FIBROUS pericardium
loosely attaches to the diaphragm.

13. The SEROUS pericardium consists of two layers:
*The __________ pericardial layer is adhered to the fibrous pericardium.
*The __________ pericardial layer lies on the surface of the heart and is also known as the EPICARDIUM.

14. Between the two layers of the serous pericardium is the pericardial space.
This is a fluid filled cavity that ________________ the two layers which allows the heart to smoothly expand and contract.

15. Beneath the epicardium is the ______cardium, the thickest layer of the heart tissue.
The inner surface of the heart that lines its chambers is the ______cardium.
Wall of the Heart

16. D A E C 4 3 2 1 B Heart = Smiley = Diamond = Cloud = 1 = 2 = 3 = 4 =

17. Cardiac Cycle ___________ –heart contracts and blood is ejected
___________ –heart relaxes and refills with blood

18. Atria relax while ventricles are contracting and vice versa
AV valves snap shut while the atria are in diastole.
Atria fill with blood from the vena cavae/pulmonary veins
Semilunar valves open while ventricles are in systole.
Blood is ejected into the aorta/pulmonary arteries
AV valves open while the atria are in systole.
Blood is ejected into the ventricles
Semilunar valves close when ventricles are in diastole.
Ventricles fill with blood from the atria
Repeat
CLOSE

20. Cardiac Conduction system
Electrical impulse for heartbeat comes from the ___________ _______ (SA node) located in the right atrium and known as the ______________ for the heart.
The SA node is a specialized area of cardiac muscle cells that can generate electrical impulses that trigger repeated beating of the heart.
Cardiac Conduction system

21. SA Node -> AV Node -> Bundle of His -> Purkinje Fibers
Current spreads across both atria and causes them to contract, pushing blood through the AV valves into the ventricles
The electrical impulse travels to the _____ _________, located near the junction of the right atrium and right ventricle.

22. SA Node -> AV Node -> Bundle of His -> Purkinje Fibers
Electrical impulse then spreads through the ______________ _____ ______ within the interventricular septum to the apex.
________________ ____________ carry impulses from the Bundle of His up into the ventricular walls. The ventricles then contract (apex to base) and blood is ejected through the pulmonic and aortic valves.

23. Normal Heart Sounds…(“lub-dub”)
Closure of atrioventricular valves at beginning of ventricular systole
“______”: S2
Closure of semilunar valves at beginning of ventricular diastole
Extra sounds = murmur

24. Valve Locations LEFT: P = Pulmonic valve A = Aortic valve
M = Mitral valve
RIGHT:
T = Tricuspid valve .

25. Heart rate – number of contractions per minute
CO (Cardiac Output)=SV (Stroke Volume) × HR (Heart Rate)
Cardiac output: amount of blood that leaves heart every minute (mL/min)
Depends on:
Stroke volume - amount of blood ejected into aorta with each cardiac contraction (mL)
Heart rate – number of contractions per minute
If a dog’s heart ejects 2mL of blood into the aorta with every contraction (SV), and its heart rate (HR) is 100 beats per minute, its cardiac output (CO) is 200mL/min.

26. Arterial wall layers are similar to the layers of the heart:
Tough outer fibrous layer
Middle layer of smooth muscle and elastic connective tissue.
Smooth inner lining called endothelium
In the aorta and pulmonary arteries, the middle layer contains more elastic fibers. This allows them to stretch slightly as they receive the high-pressure blood from the ventricles.
Vascular Anatomy

27. Vascular Anatomy Continued
-Arteries lead to arterioles, then capillaries. -Capillaries consist of only one cell layer (simple squamous epithelium). It is easy for the blood to exchange oxygen and nutrients for carbon dioxide and vice versa. -Capillaries lead to venules, then veins.

28. Vascular Anatomy Continued
Venous blood is under __________ pressure than arterial blood
Veins have _________ walls than arteries
_________ in veins ensure that blood travels only toward heart
Veins usually are located next to arteries.

29. Vascular Anatomy and Physiology
Blood in the systemic circulation is under higher pressure than blood in the pulmonary or coronary circulation. More pressure is needed to carry blood throughout the body.
The systemic circulation encounters more resistance to flow.
With the exception of the pulmonary arteries and veins and the umbilical arteries and veins, arteries carry _____________ blood and veins carry _______________ blood.

30. Right and left subclavian arteries travel to forelimbs.
Carotid arteries supply blood to the head.
Main trunk of aorta arches and then travels caudally.
Numerous branches emerge in the thoracic and lumbar areas
At hind limbs, aorta branches into Right and Left External Iliac arteries which supply hindlimbs.
Small Coccygeal artery emerges to supply blood to tail.
Vascular Anatomy

31. Vascular Anatomy Continued
Jugular veins drain blood from the head.
Veins in the foreleg merge into larger and larger vessels to form right and left Brachiocephalic veins
These carry blood to the Cranial Vena Cava then back into the right atrium.
Veins in the hind limbs merge into Common Iliac veins which also unite with the Caudal Vein
Blood then enters the Caudal Vena Cava.
Caudal vena cava travels to the Right Atrium