Biology 12: Circulatory System Name:_________________________________

The Circulatory System Notes Package

Heart

● Pump __________________ throughout the body

Blood

● Carry ________________ from ________________ & nutrients from intestines to cells ● Carry carbon dioxide to lungs & _________________ to kidneys ● Helps fight _______________________ ● Helps regulate __________________temperature ● Coordinates activities of ______________________ – ie. Provides a

________________________ for hormones

The Blood Vessels (pg. 298-299)

Circulatory system has 3 types of blood vessels:

1) Arteries (and arterioles)

● Always carry blood________________ from the heart *always true*

● Can _______________ to carry large amounts of blood

● Arterial walls have 3 layers: o Innermost layer – endothelium o Middle layer of elastic and muscle; thickest layer consisting of

_______________________ ▪ Elastic- can expand and contract with

_____________________ (pulse) ▪ Muscle provides strength; allow constriction/dilation (blood flow

control) ▪ So __________________- that arterioles have to provide

nutrients/O2 o Outer layer- fibrous _______________________

● Smaller arteries branch off from the aorta forming large number of ______________________

● Arterioles o Middle layer composed of some elastic tissue but mostly smooth muscle o Constriction/dilation affect _______________________________

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2) Capillaries

● Very _____________________, are 1 cell layer thick -> faster and ______________________diffusion/osmosis

● so small that red blood cells can only move in _______________________ ● Play important role in homeostasis (balancing the internal environment) ● Services all cells

o Carry __________________________ to cells o Remove CO2/wastes (e.g. ammonia – byproduct of protein metabolism)

from cells o Thoroughfare channel- carry blood from

______________________________ o Have ______________________on arteriole end to help

regulate______________________

3) Veins

● Venules (small veins) _______________________ from capillaries + join to form a vein

● Carry blood from capillaries _________to the heart ● Same three layers as arteries but

_____________________________________

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● No blood pressure to force blood through: o 1) Rely on one-way valves – allow blood to flow in one direction

▪ Found in veins that carry blood _______________________ e.g. limbs

o 2) Skeletal muscle contraction-surrounding muscles contract and squeeze

the vein

o 3) Breathing also creates a _______________ difference that helps _________________ ● **Broken down valves can cause pooling of blood causing veins to be

enlarged, this is known as varicose veins

Characteristics of the Heart

● Cone-shaped, ___________________ organ the size of a fist

● Located between the lungs behind the breastbone ● Apex (pointy part of heart) pointed to body’s left ● Consists mainly of cardiac muscle tissue known as

____________________ ● Heart lies within

the___________________________, thick serous that secretes small amount of ______________________

● The ___________________ separates the heart into a right and left side.

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4 chambers:

● 2 atria located above (thin-walled)- pump blood to the ______________________ ● 2 ventricles (thick walled) – pump blood to ____________________________

Valves in the Heart

● 4 valves that direct flow of blood and prevents it going backward:

● 1) Atrioventricular Valves- between _________________________

● Supported by strong fibrous strings called ____________________ (attached to ventricular wall)

AV Valve on right side = ____________________

AV valve on left side = __________________________

Think LAB RAT: Left Atrium, BicuspidRight Atrium, Tricuspid

● 2) Semilunar valves- between ventricles and their attached vessels, causes flow in one direction

● Pulmonary semilunar valve – between the ____________________ and ______________________

● Aortic semilunar valve- between left ventricle and the aorta

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Parts of the Heart

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Blood Flow through the Heart

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How the heartbeats

● Each heartbeat is called a ____________________ ● When it beats:

○ The _______________________ contract first at the same time ○ Then _______________________ contract at same time ○ Then all chambers _____________

Systole vs Diastole

● Systole refers to _________________of heart muscle ● Diastole refers to__________________ of heart muscle ● Each heartbeat lasts 0.85 seconds ● Normal Blood Pressure: ________________(systolic: diastolic pressure)

Heart Conduction System

● SA node sends out a ______________, causing atria to contract.

● Stimulus reaches _____________________, signals ventricles to contract

● Impulses pass down two branches of ___________________ to ___________________

● Ventricles contract

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Controlling the Heart Beat

Intrinsic control:

● Controlled by __________________ (has muscular and nervous characteristics) ● SA node aka ___________________r initiates heartbeat and send out an excitation every

0.85 sec ● Keeps heartbeat at a regular pace ● Impulse sent to _______________ causing ventricles to contract, slight delay allows

___________ to finish contracting first ● If SA node fails to work properly, heart still beats due to impulses generated by AV node

Extrinsic(External) Control:

● ______________________, part of the brain that controls internal organs, can change heart beat via the _____________________ (in nervous system)

○ 2 ways: parasympathetic and sympathetic system ■ Parasympathetic division

○ - promotes functions of a _____________________ ■ Sympathetic division

- _______________________; brings about responses to increased activity or stress

Real life Applications

● ECG: ____________________, A recording of electrical activity in the heartbeat during a cardiac cycle

○ Normal ECG indicates heart is functioning properly:

● ___________________ occurs just before _______________contraction ● ________________ happens just before __________________________ ● _______________ occurs when ventricles are ___________________from contraction

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Blood Pressure _

A measurement of the _____ _________ pushing against the _________________ of blood vessels

Blood pressure in Arteries

● _____________ and _____________ of blood are in high in arteries ● When the left ventricle contracts, blood is forced into the __________ and then into other

___________________ under pressure ● Systolic pressure: results from blood being forced into arteries during

ventricle_______________ ● Diastolic pressure: pressure in the arteries during ventricular __________________

Blood pressure in capillaries

● Blood flow in the capillaries is slow and even. ● Blood pressure is under ________________ and has ___________________

o The low velocity also ensures diffusion of oxygen and carbon dioxide and wastes ● Capillaries have a high cross-sectional area meaning __________________ for materials to

efficiently pass across vessels and surrounding cells. Blood pressure in Veins

● Pressure is __________ and __________________ to move blood back to the heart especially from limbs (legs and arms)

o Ways blood gets back: -Skeletal muscles near veins contract putting pressure on veins and blood it has -Valves preventing backward flow of blood

What happens to blood pressure progressing through body?

● Blood pressure gradually falls as blood flows from ____________into ________________ and into _______________

● The difference between your systolic and diastolic pressure goes down and nearly diminishes

Our Blood Pressure What is a normal blood pressure reading (systolic : diastolic)? _________/__________

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● Blood pressure can be measured with a ___________________________ o Sphygmomanometer: pressure cuff that determines amount of pressure required to

_____________ of blood through an artery o Expressed in millimeters of ____________________(_________)

BLOOD PRESSURE CATEGORIES

Category Systolic / Diastolic

Low risk 120 / 80

Medium risk 121-139 / 80-89

High risk 140+ / 90

Disorders Hypertension (pg. 322 in Textbook)

● 1 in 5 Canadian adults have high blood pressure ● Under 45 years of age with blood pressure of _____________________ mm hg is abnormally high ● Above ____________________ in older people ● Pre-cursor is pre-hypertension ● Can be caused due to person’s arteries becoming narro for blood flow

o Causes a lot of pressure made to force blood through o Can damage heart, vessels and other organs

● Treatments for Hypertension: o ____________________(makes you pee a lot to reduce blood volume) o Vasodilators- increases __________________ of blood vessels making it less restricting for

blood to flow Hypotension

● Optimal blood pressure is less than 120/80 (systolic pressure is 120 AND diastolic pressure is less than 80)

● No specific blood pressure that is ‘low’ o symptoms of low blood pressure: dizziness, fatigue, and nausea

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Vascular Pathways

The circulatory system includes two circuits.

The_________________________circulates blood through the lungs and the _______________serves the needs of body tissues.

The Pulmonary Circuit

● Blood from all regions of the body gets first collected in the

_______________________and then passes into the right ventricle which pumps it into

the ______________________________. ● The pulmonary trunk divides into the right and left

____________________________which branch as they approach the lungs. The

arterioles take blood to the pulmonary capillaries, where

_______________________occurs.

● Blood then passes through the pulmonary _____________________which lead to the

_________ pulmonary veins (two from each lung) that enter the left atrium.

● However because pulmonary arteries is _______________ (deoxygenated) but blood in

pulmonary veins is _________________, it is not correct to say that all arteries carry blood

high in oxygen and all veins carry blood low in oxygen.

**In the pulmonary circuit this is the opposite **

The Systemic Circuit

● This circuit includes the major arteries and veins. The largest artery being the ____________; the largest veins being the _______________________.

● Superior vena cava collects blood from the ___________________________. Inferior

vena cava collects from ______________________________. Both enter the right

atrium. ● Path of the systemic blood to any organ in the body begins in the

_______________________. ● For example, trace the path of blood to and from the legs:

Left ventricle → aorta→ common iliac artery→ femoral artery→ leg capillaries→ femoral vein→ common iliac vein→ inferior vena cava→ right atrium

Notice when tracing the blood, you only need to mention the aorta, proper branch of the aorta, the region, and the vein returning the blood to vena cava.

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● ________________________ serve the heart muscle itself (heart is not nourished by the

blood in its own chambers itself).

● are the______________________________________ off the aorta.

● originate just above the _________________________________and lie on the outside of the heart

Portal systems

● begins and ends in _____________________________. ● Hepatic portal system is associated with the ________________. Capillaries occurring in

the villi of small intestine pass into venules to form the

_____________________________ ● vein carries blood to a set of capillaries in liver, this then leaves liver and enters into the inferior

vena cava

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The Components of the Blood Functions of the Blood: 1. Transport- Helps in transporting O2 & nutrients and wastes CO2, and __________________________ 2. Regulation: Regulates ______________________________ by releasing heat; regulates blood pressure due to protein in blood

Maintains blood pH about 7.4 3. Protection- Protects against invasion by disease-causing pathogens( viruses, bacteria)

Blood clotting mechanism- protects the body from losing blood

If blood is collected into a test tube, it separates into 3 layers.

1. Plasma: ______________________________ that makes up about 55 % of blood. 2. Formed (solid) Elements: 45%

--Erythrocytes (RED BLOOD CELLS) -- _____________________________(WHITE BLOOD CELLS) -- Thrombocytes (PLATELETS)

CONSTITUENTS OF PLASMA Type _ Function Water (90%) Maintains blood volume.

Transport of cells and materials. Plasma Proteins Helps maintaining Osmotic pressure and pH in blood

Transportation i) Albumen Thickens blood, Transports, maintains blood volume, Osmotic

pressure ii) Fibrinogen Blood Clotting iii) Globulins Infection fighting

Gases i) Oxygen (trace amount) Cellular Respiration ii) Carbon Dioxide Waste product Nutrients (Lipids, glucose, and amino acids) Food for cells. Nitrogenous Wastes Waste products of all

cellular reactions. Other (hormones, vitamins Aid in metabolism Etc.)

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Formed Elements The Red Blood Cells (erythrocytes)

− manufactured in the ______________________: Site of the origination of ALL types of blood cells.

− live for about 120 days (destroyed in liver and spleen with some parts recycled) − mature RBCs: _______________________(shape increases flexibility for moving through

capillaries and surface area for diffusion of gases. − they do not have a nucleus − Carry O2 because they have _______________________ − ______________________: respiratory pigment, it’s what gives RBCs

their color − contains four polypeptide chain; each has iron-containing group (Heme

groups) that picks up and releases oxygen

The White Blood Cells (leukocytes) − are usually larger, amoeboid-like shape, have a nucleus, do not have

hemoglobin − not as numerous but help _____________________ and have some role in developing

_________________________ − originate from the red bone marrow

The Platelets (thrombocytes) − disk shaped cell fragments with _________________;

originate from the red bone marrow − involved in the process of

_________________________________

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The Lymphatic System and Tissue Fluid

The lymphatic system is another vascular system in your body. ● separate from your circulatory system but eventually connects back by emptying

into_________________________ ● system takes up _________________________________(fluid that surrounds cells and tissues) from

the ______________________________and returns it to circulatory system ● It is a __________________________ system that starts in the tissues and empties into the

circulatory system Functions of the Lymphatic System

1. Transport of excess tissue fluid back to circulatory system 2. Absorption of fat from the intestine and transport to blood 3. Fighting infection by ___________________________________ and production of

____________________________________ (a type of white blood cell). Some lymphocytes produce antibodies

Lymph vessels

● LYMPH CAPILLARIES and ___________________________________(which have valves). ● fluid in lymph vessels is called ___________________________________-

● Lymph is collected in vessels that join to form two main trunks that later drain into the

circulatory system via: o Right Lymphatic duct: empties lymph into __________________________________ o Thoracic duct: empties lymph into ________________________________________

LYMPH NODES: small oval or round structures that occur along ____________________________________ on lymph vessels. They produce and store special type of white blood cells (lymphocytes) , and _______________________________________________for damaged cells and debris. Capillary Exchange As blood passes through the capillaries, about 10%

of its fluid leaks into the surrounding tissues. This is known as _____________________________________. This fluid carries chemicals such as glucose and hormones to the cells of the body, and removes waste products, such as urea and CO2.

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Movement of fluid is controlled by: 1) Osmotic Pressure- created by _________________________________________________ (causes water to move from tissue fluid to blood) 2) Blood pressure- causes water to move in the _______________________________________________

Diagram of blood flowing through capillary At arteriole end (starting from left of diagram)

● Blood pressure is ______________________________than osmotic pressure at arteriole end

● Halfway through capillary _______________________________ two forces cancel out; no net

movement of water

o Solutes can diffuse now according to their __________________________________________

▪ Nutrients (glucose and amino acids) and ____________________________________of

capillary into body tissues

▪ CO2 and wastes diffuse into the ______________________________

● Red blood cells and plasma protein are inside capillary but small substances leave adding to

the _________________________________(interstitial fluid) – fluid between body cells

At venous end of capillary (far right of diagram)

● BP has fallen, osmotic pressure is higher ● Water tends to move into capillaries ● Excess fluid is always collected by lymphatic capillaries ● Lymph is returned to systemic venous blood

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