Unit 13: Circulatory System

Systemic Circulation – delivers blood to all body cells and carries away waste

Pulmonary Circulation – eliminates carbon dioxide and oxygenates blood (lung pathway) 

Structure of the Heart

Heart Size – about 14 cm x 9 cm (the size of a fist). 

Located in the mediastinum , between the 2nd rib and the 5th intercostal space. 

The distal end of the heart is called the apex.

CORONARY ARTERIES

A blockage in these arteries causes a “heart attack”

Fibrous Pericardium encloses the heart
(like a bag) and has 2 layers 

Pericardial cavity – contains fluid  reducing friction

Wall of the Heart 

• Epicardium – outer layer, reduces friction

• Myocardium – middle layer, mostly cardiac muscle

• Endocardium – thin inner lining, within chambers of the heart

Blood Flow in the Heart

Your heart is a DOUBLE pump  (double - loop circulation) 

Pulmonary - blood travels to the lungs and then back

Systemic - blood travels to the body and then back to the heart

Heart has 4 chambers: 

2 Atria – thin upper chambers that receive blood returning to the heart through veins

2 Ventricles – thick, muscular lower chambers.  Pumps blood out of the heart through arteries (away). 

Septum – separates the right and left sides of the heart

Valves of the Heart – allow one-way flow of blood.      
        2 Atrioventricular Valves  & 2 Semilunar valves          (4 total)

Left Atrioventricular valve – also called the bicuspid valve or mitral valve. 

Right Atrioventricular valve – also called the tricuspid valve. 

Aortic Semilunar – or just aortic valve. Between the left ventricle and the aorta

Pulmonary Semilunar, or just pulmonary valve. Between the right ventricle and the pulmonary artery

The cusps (flaps) of the bicuspid and tricuspid valves are anchored to the ventricle walls by fibrous “cords” called chordae tendineae, which attach to the wall by papillary muscles. This prevents the valves from being pushed up into the atria during ventricular systole.

Septum - muscular wall that divides the left and right side of the heart

Ventricular or Atrial Septal Defect: Sometimes called a “hole in the heart”

Mitral = bicuspid (left side)
Tricuspid (right side)

Aortic and Pulmonary are both semilunar valves
Platelets (thrombocytes)

- help initiate formation of blood clots, close breaks in damaged blood vesselsBlood Plasma

The liquid portion of blood is

92% water

- transport nutrients, gases,

vitamins, maintain fluid and

electrolyte balance, and pH Plasma Proteins

● Albumins – blood pressure

● Globulins – transport antibodies

● Fibrinogen – blood clotting

Multiple myeloma is cancer that affects

plasma cells, these cells crowd out

healthy cells and produce antibodies that

may attack the body’s own tissues.

HEMOSTASIS

- process of stopping bleeding

- Involves the coagulation and clotting of

the blood to seal the site of damage

*To perform emergency first aid, bleeding

can be slowed by pressure

A tourniquet can also be used.

See demonstration on how to apply a

tourniquet.KEY EVENTS IN HEMOSTASIS

1. Blood Vessel Spasm

Serotonin (vasoconstrictor)

shrinks the vessel

2. Platelet plug formation -

closes the opening

3. Coagulation - Fibrin forms over

the plug and reinforces

* forms a scab THROMBIN - an enzyme in blood plasma that causes

the clotting of blood by converting fibrinogen to fibrin.

COAGULATION -

the thickening of

blood to form a clot

(hematoma)

Video: Platelets and Blood ClottingTHROMBUS – blood

clot (abnormal)

EMBOLUS – when the

clot moves to another

place.

* Pulmonary Embolism -

when a blood clot goes to

the lungs * Cerebral Embolism - when

a blood clot goes to the brainWhy are newborns given Vitamin K injections?

Babies can be given the injection in hospital after

they’re born. In newborns, vitamin K can prevent

a bleeding disorder called ‘vitamin K deficiency

bleeding’ (VKDB)HEMOPHILIA

“Bleeder’s disease”

Carried on the X chromosome

Passed from mothers to sons.

Blood does not clot, leading to

crisis even with minor injuries.Blood Donations

Blood is removed from the

brachial vein.

The average adult has 10

pints of blood in the body

(that’s about 5 liters).

Most donations take about 1

pint of blood (½ liter).Plasma can also

be donated.

This machine

removes the

plasma from the

blood and returns

the RBC’s to the

donor. How is donated blood used?

Patients with hemophilia (blood

and clotting factors are

replaced)

Patients with sickle cell to

reduce sickle cells

Replacement of blood after

injury or surgery.

White Blood Cells

Guided Notes Handout

On the 4th May 2020, Isla-Mae was rushed

to hospital after a few weeks of high

temperatures and swollen tonsils. Doctors

suggested it was a case of tonsillitis, but

she wasn’t getting any better. Her parents

noticed that there was red spots and

bruising all over her body. She was rushed

back to the hospital.

- Suggest some possible causes for

Isla-Mae’s symptoms

This case story follows Isla-Mae’s diagnosis.

Details of a typical case are added. To diagnose Isla- Mae, several tests were

performed.

Doctors drew a sample of her blood and

sent it to a pediatric oncologist. A complete

blood count, CBC, is done to determine the

the number of different types of blood cells

found in the sample.

The image represents a blood sample taken

from someone with Isla’s condition. What do

you notice?

Would the hematocrit be within the normal

range?A bone marrow biopsy was also completed

to confirm confirm the diagnosis.

Isla-Mae had leukemia, a type of blood

cancer.

Acute lymphoblastic leukemia, or ALL, is

the most common type of childhood

leukemia, making up at 75% of all cancers.

(Source: MD Anderson)

Acute = a cancer that progresses quickly

Lymphocytic refers to its effect on cells that

turn into healthy white blood cells

Isla-Mae would need to start

chemotherapy right away. How does leukemia affect

the body?

There are several types of

white blood cells that are

involved in maintaining the

body’s homeostasis.

When these cells don’t work

correctly, then many body

functions are disrupted.

To understand why

homeostasis is disrupted, we

need to understand how

white blood cells work. Essential Question: How does blood maintain

homeostasis?WHITE BLOOD CELLS (Leukocytes)

* Granulocytes (granular cytoplasm)

Neutrophils, Eosinophils, Basophils

* Agranulocytes (lacking granular cytoplasm)

Monocytes, Lymphocytes

Complete this chart as we

discuss the types of blood cells.6

The white blood cells are found within the red blood cells, there

are not as many WBC’s and generally, they are larger than RBC’s.Chart lists the normal

percentages of each type

within a blood sample.

Irregularities in this number

can indicate a disease.

Example: Elevated numbers

of eosinophils may indicate a

parasitic infection.

The next slides will outline the

function of each type.

Complete the chart as we go.Neutrophil (nucleus has several lobes)

-Active phagocytes

-60% of WBC

-Present in the pus9

neutrophil (yellow)

phagocytosing anthrax

bacilli (orange)Eosinophil

Mainly attack parasites

2% WBC

Schistosome worm(1%)

Basophil Produces Heparin = blood

thinner

Histamines = Important in

inflammatory reaction

Histamines cause

swelling and itching.

Antihistamines

suppress this reaction.Dermatographia:

Immune system releases

excess amounts of

histamine causing welts

to appear when lightly

scratched.

Cold Urticaria (essentially

meaning "cold hives") is an

where hives or large red welts

form on the skin after exposure to

a cold stimulus.13

Monocyte (large cell, horseshoe shaped nucleus)

Can become macrophages or

dendritic cells

Dendritic cells consume

pathogens and then present

antigens on their surface to signal

the immune systemLymphocyte

(nucleus is dark and takes up

almost whole cell)

LYMPH

NODES

Main defense

(immune system)

Produce ANTIBODIES

30% WBCMononucleosis

sometimes called "mono" or "the kissing

disease," is an infection usually caused

by the Epstein-Barr virus (EBV).

The designation "mononucleosis" refers

to an increase in one type of white blood

cells (lymphocytes) in the bloodstream

EBV is very common, and many people have been

exposed to the virus at some time in childhood. Article at

Medicinenet

Treatment: It just takes time and rest for the body to

recover from the virus.Human Immunodeficiency Virus (HIV)

HIV weakens the immune system by infecting

specific immune cells. (CD4 T-cells; )

A person can be infected with HIV and not

have AIDS. Infection occurs from exposure

to body fluids, like blood or semen.

AIDS = acquired immune deficiency

syndrome

*When the number of CD4 cells falls below

200 cc’s, a person can develop opportunistic

infections.

There is no cure, but antiviral drugs can slow

the progression of the disease.Left: Lymphocyte | Right: NeutrophilWhy is Isla-Mae so sick?

Summarize the changes that take place

when white blood cells do not function.

The main treatment for leukemia occurs in

three phases:

1. Remission Induction

2. Consolidation

3. MaintenanceIn phase one, chemotherapy is used to

stop the growth of cancer cells.

Drugs that target cancer cells also can

damage healthy cells. Chemotherapy

can cause hair loss, digestive issues,

decline in red blood cells, and suppress

the immune system.

Isla-Mae underwent chemotherapy

during the Covid-19 pandemic.

What challenges did the pandemic have

What is chemotherapy like for children

(Youtube, ~4 min)

for cancer patients?Other therapies:

● Radiation Therapy

● Stem Cell transplants

● Bone Marrow Transplants

● Immunotherapy

What are the survival rates

for childhood ALL?

Ian is a happy normal toddler when his

pediatrician noticed that his abdomen

was swollen. The doctor ordered a CT

scan to determine if there was

anything wrong.

What might be some causes of a

swollen abdomen?

Red blood cells carry oxygen and nutrients

throughout the body. It’s unique structure allows it to

grab onto iron and oxygen for transport.

White blood cells have an immune function.

Guided Notes Handout2

The CT scan of Ian’s abdomen identifies

SPLENOMEGALY, which is an enlargement of the

spleen. Can you locate the spleen?

The doctor assured the parents that there are many

causes for an enlarged spleen and it is not life-threatening

at this point. The following is a list of possible causes.

● Leukemia

● Mononucleosis (viral)

● Sickle Cell Disease

● Beta Thalassemia

● Malaria

● Thrombocytopenia

Which disorder on the list that is probably the least likely

for a kid living in Chicago.

The doctor orders additional blood

tests to determine the cause of Ian’s

enlarged spleen.

Functions of the spleen:

● filters the blood

● removes old blood cells

● recycles iron

● makes antibodies

SPENIC

CELIAC

AORTA

Sketch and label the arteries that

supply blood to the spleen.

Source: WebMD4

The lab delivers the results of the blood test

and the doctor shares his observations

● blood cells appear normally shaped

● red blood cells have a low count

● no abundance of white blood cells

● RBC’s appear pale

Ian’s blood has hypochromia.

What does that mean?

PHLEBOTOMIST -

person trained to draw

blood from a patient

Ian’s Cells

Normal

White blood cell5

The doctor orders additional tests but delivers some

bad news to Ian’s parents. “It looks like Ian has

Cooley’s anemia, which is an inherited disorder that

interferes with the blood’s ability to carry oxygen. It’s

very typical for the cells to appear faded

(hypochromia).”

Fortunately for Ian, there are treatments available,

mainly he will need regular blood transfusions to

replace his abnormal blood with blood that functions.

Cooley’s anemia, also known as Beta-thalassemia

is a recessive disorder. Ian’s parents were carriers

(Bb x Bb). What is the chance that his parents

would have a child with the disorder

(bb)?

B

b

B b6

Blood and Blood Cells

Why didn’t Ian’s blood cells work?

Blood is a type of CONNECTIVE TISSUE

It has two basic components:

-CELLS (rbc, wbc, platelets) = 45%

-Plasma (water, proteins, amino acids) = 55%7

To determine the percentages, blood is

placed in a centrifuge. Heavier cells

settle to the bottom of the sample.

Hematocrit the percentage of

blood & plasma

blood cells = 45%.

fluid (plasma) = (55%).

Would Ian have a normal hematocrit?

Why or why not?

Investigation: Hematocrit8

Three Types of Blood Cells

Erythrocytes = red blood cells

Leukocytes = white blood cells

Thrombocytes = platelets

How does the shape of the blood differ

in those with beta thalassemia?

How does the shape of the blood differ

in sickle cell versus beta thalassemia?

Sickle Cell

Normal Blood

Beta Thalassemia9

Red Blood Cells (RBC)

- made from a protein called hemoglobin (Hb)

which contains iron used to transport oxygen.

- Shape = Biconcave discs

- 5 million per cubic millimeter (drop)

- contain no nuclei

What could happen if a person has a low

amount of iron in their diet? (This

condition is called iron-deficient anemia.)10

Normal red blood cells do not contain a

nucleus. The dark areas within the cells

on the image are nucleated blood cells.

Ian’s blood contained nucleated cells,

which is associated with Beta

Thalassemia.

Nucleated cells

found in Ian’s blood

Question: If RBC’s don’t contain a

nucleus, then how do forensic scientists

get DNA from blood samples?

Side note: Mammals are the only vertebrates that have

enucleated (no nuclei) blood cells. As part of the maturation

process in the bone marrow, the nucleus is pushed out.11

HEMATOPOIESIS - formation of blood cells

- occurs in the bone marrow

- an error in the genetic code can cause the

protein to be abnormally shaped

Compare the genetic codes of

normal DNA to that of B

thalassemia. What is different?

Source: NEJM12

Hemoglobin and Genetics

Changes in the hemoglobin protein alter its

oxygen-carrying ability.

Another blood disorder is sickle cell anemia.

A single change in a base changes the amino

acid, which changes the protein...

Caused by a recessive

gene (aa)

Symptoms:

● lethargy

● pain

● stroke

● organ failure13

EPO, or erythropoietin, is a hormone that increases production of RBC’s.

2013 - The International Olympic Committee

strips Lance Armstrong of the bronze medal

he won at the 2000 Olympic Games in

Sydney, Australia for using

performance-enhancing drugs.

Do you think that someone with beta

thalassemia could be treated with

EPO? Why or why not?

Athletes sometimes train at high

altitudes which will increase the

amount of EPO. What effect would

this have on their performance?

Blood Feedback Loop Assignment14

Oxygen Levels

Oxyhemoglobin = plenty of oxygen; “bright red”

Deoxyhemoglobin = low in O2, “dark red”

Blood delivers oxygen to tissues and then returns to the

heart through veins. The heart sends blood to lungs where

it is oxygenated and sent to tissues via arteries.

Veins and arteries meet at tiny vessels called capillaries,

which deliver to tissues.15

It is a myth that deoxygenated blood appears blue.

The blood on the left is oxygenated, the right is

deoxygenated blood from a vein (Source: Wikipedia Commons)

Identify the blood in the syringes that

was drawn from an artery

Sickle Cell Disease

- a genetic mutation in the DNA code

- incorrect formation of the hemoglobin protein

- cells are abnormally shaped

- cannot carry oxygen efficiently

The disorder is caused by a RECESSIVE (or

codominant) gene. Parents can be carriers.

A a

Person with

sickle cell

trait

A AA Aa

a Aa aa

Person with

sickle cell

disease

Practice with Sickle Cell Genetics18

Symptoms of Sickle Cell Anemia

- splenomegaly

- fatigue / weakness

- pain crisis

- strokes

- shortness of breath