Circulatory System Chapter 4

Veterinary Technology

Introduction Vertebrates have a closed circulatory system,

which generally confines blood within its walls. The closed systems coevolved with the respiratory

and lymphatic systems. In fish, blood flows in one circuit. In birds and mammals, it flows in two through a

partitioned heart that works as two side-by-side pumps.

The double circuit supports the high levels of activity typical of most vertebrates that evolved on land.

Blood Components and Functions When blood is spun in a centrifuge, the

liquid and solids portions separate and the solids settle to the bottom.

This cellular portion makes up about 30% to 45% of total blood contents.

The remaining fluid is plasma.

what’s in

red blood cells

white blood cells

platelets

plasma

carbon dioxide

digested food

waste (urea)

hormones

oxygen

The Blood

plasma

red blood cell

white blood cell

platelets

Red Blood Cells – AKA Erythrocytescontain hemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it.

can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries.

a biconcave disc that is round and flat without a nucleus

An adult dog has about 6 to 8 million RBC’s per microliter!

Red Blood Cells – AKA Erythrocytes Erythropoieses = the production on RBC’s

by the bone marrow. Erythropoietin = hormone produced in the

kidney to stimulate RBC production. When and why do animals need this?

White Blood Cells – AKA Leukocytes

there are many different types and all contain a big nucleus.

the two main ones are the lymphocytes and the macrophages.

some lymphocytes fight disease by making antibodies to destroy invaders by dissolving them.

other lymphocytes make antitoxins to break down poisons.

macrophages ‘eat’ and digest micro-organisms .

Blood Components and Functions Types of White Blood cells – page 48 Types of Blood proteins – page 46

PlateletsPlatelets are also produced in the bone marrow, help with blood clotting.

Platelets produce tiny fibrinogen fibers to form a net. This net traps other blood cells to form a blood clot.

Platelets work with the protein Fibrinogen

What is the process of blood clotting?

Plasma – about 94% water

A straw-colored liquid that carries the cells and the platelets which help blood clot.

• carbon dioxide

• oxygen

• nutrients

• glucose

• electrolytes

• proteins – about 8%

• minerals

• vitamins

• hormones

• waste materials like urea.

It also contains useful things like;

Directional Terminology Helpful to know, when describing

anatomy and describing blood flow.

Medial refers to being directed toward the middle or median plane of the body. The median plane is best

described as a line that would divide the body in half from head to tail.

2. Lateral refers to being directed away from the median plane of the body

1. Cranial is directed toward the head or cranium. It is used on the legs to describe

structures above the metacarpal/ankle/fetlock joint.

Dorsal is used to describe structures below the aforementioned joint, along with palmar or plantar.

2. Caudal is directed toward the rear of the body. It is used for structures on limbs above

the metacarpal/ankle/fetlock joint.

1. Dorsal refers to a body part that is directed toward the back of the body. For instance, the hip joint is

dorsal to the knee joint.2. Ventral refers to a body part

that is directed toward the belly. For example, the elbow joint is

ventral to the shoulder joint

1. Proximal is directed toward the body from foot to head.

2. Distal is directed away from the body from head to foot

Blood Vessels and Blood Flow

In Mammals, The heart is a four-chambered, hollow muscle used to pump blood. It provides two separate paths.

1. Pulmonary Circuit: moves blood to lungs. Right Ventricle is the pump

2. Systemic Circuit: moves blood to the rest of the body. Left Ventricle is the pump

Blood Vessels and Flow Page # 52 may be more helpful than my

description. Be sure and read this section! (pages 50

– 54)

Lungs

Body cells

Mammal’s circulatory system is a double circulatory system.

This means it has two parts .

the right side

(Pulmonary) of

the system

deals with

deoxygenated

blood.

the left side

(Systemic) of

the system

deals with

oxygenated

blood.

How does the Heart work?

blood from the body

blood from the lungs

The heart beat begins when the

heart muscles relax and blood

flows into the atrium. The

relaxation phase is called the

diastole phase

STEP ONE: The Cardiac cycle

The atrium then contract and

the valves open to allow

blood

into the ventricles. The

contraction phase is called

systole.

How does the Heart work?

STEP TWO: The Cardiac Cycle

How does the Heart work?

The valves close to stop blood

flowing backwards.

The ventricles contract forcing

the blood to leave the heart.

At the same time, the atria are

relaxing and once again filling with

blood.The cycle then repeats itself.

STEP THREE: The Cardiac Cycle

Mammalian Heart Structures The heart is located low in the chest between the

two lungs, and is contained within a fine membrane,

called the pericardium. The wall is mainly composed of cardiac muscle, the myocardium. Smooth epithelium tissues lines both the inside and outside of the myocardium.

There are 3 types of blood vessels

a. ARTERY

b. VEIN

c. CAPILLARY

The ARTERY

thick muscle and elastic fibers

Arteries carry blood away from the heart.

Break down into smaller arterioles as they reach the lungs

the thick muscle can contract to push the blood

along.

the elastic fibres allow the artery to stretch

under pressure

The VEIN

Veins carry blood toward the heart.

thin muscle and elastic fibers

veins have valves which act to stop the blood from going in the wrong direction.

body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push the blood along the vessel.

The CAPILLARY

Capillaries link Arteries with Veins

the wall of a capillaryis only one cell thick

they exchange materials between the blood and other body cells (tissues)

The exchange of materials between the blood and the body can only occur through capillaries.

artery vein

capillariesbody cell

The CAPILLARYA collection of capillaries is known as a capillary bed.

SUMMARY

copy and complete the following;

Arteries take blood ______ from the heart. The walls of an artery

are made up of thick _________ walls and elastic fibres. Veins

carry blood ________ the heart and also have valves. The

_________ link arteries and veins, and have a one cell thick wall.

Blood is made up of four main things ______, the liquid part of

the blood; Red Blood Cells to carry ______; White Blood cells help

to protect the body from disease and _________ help blood clot.

away

platelets

towards

capillaries

plasma

oxygen

muscular

Electrocardiograms, Heart Sounds and Blood Pressure The rate at which the heart beats is

controlled by the nervous system. Pacemaker cells (system): the cells that

begin the heartbeat, and help control the rhythm. AKA: Sinoatrial (SA) node Found in the right atrium

Blood Pressure The highest numbers is both the systole

and diastole phases. Measured in millimeters of mercury Typical human is 120/80 mm Hg. Systolic over diastolic pressure Doppler machine http://www.youtube.com/watch?v=no7Z8H8yCyQ

Blood Pressure Ways to regulate BP:

BP is higher is arteries than veins Page 59 Kidneys produce a enzyme called renin

when a low BP is detected. BP is lower in the limbs (fight gravity)

Why do you faint when you lock your knees?

Electrocardiograms, Heart Sounds and Blood Pressure Electrocardiograph – the instrument that

picks up the electrical signal running through the body

Electrocardiogram – (ECG) the tracing made by the instrument. Identifies problems associated with the

contraction of the heart.

Electrocardiograms, Heart Sounds and Blood Pressure sinus rhythm = Normal, consistent rate Sinus trachycardia = faster than normal,

but with a normal rhythm Sinus bradycardia = slower that normal,

but with a normal rhythm Artial fibrillation = pacemaker not

working, irregular Asystole = flat line!

Cardiopulmonary resuscitation (CPR)

Electrocardiograms, Heart Sounds and Blood Pressure

Heart murmurs: defective valve or abnormal flow of blood. Makes a swishing noise In you notes: read page 56: Describe the

typical heart noise and the action that happens for that noise to occur.

Science Starter Read page 45 What will happen to Sconic’s foot when

the blood supply was stopped? For a short period of time For a long (several days) period of time?

Clinical Practice Blood analysis is the process of testing blood to

determine its characteristics. Samples are collected and tested to determine

various attributes.

Clinical Practice Blood typing is a kind of analysis that is used in

genetic studies. Genetic markers in the blood can be used to

determine the parents of offspring. For example, the identity of the sire of a calf can be

determined by blood typing a calf. Newer DNA analysis procedures may be replacing

some uses of blood typing.

Capillary Refill Time (CRT) Check on gums, tissues under nails. 1. Apply pressure for 5 seconds 2. remove the pressure In a healthy animal , the color should

return to pink in just one second!

Clinical Practice: vocab! Hypo- (value is below normal) Hyper- (value is above normal) -enima (used to describe levels in the blood

stream -penia (WBC count less than normal) -cytosis (WBC count higher than normal) -ia (other cells are elevated) Erythro- (referring to RBC) Auto- (referring to self)

Anemia Low RBC count Supplies less oxygen to the tissues Signs: fatigue during exercise, weak, sluggish,

inactive. Not an actual disease – sign of other diseases Causes:

1. excessive blood loss 2. shortened life of RBC 3. decreased production of RBC

Parasites??? (hookworm) Acetaminophen (Tylenol) Autoimmune Disease