biology 11 cadriovascular unit notes

7/27/2019 Biology 11 Cadriovascular Unit Notes

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Circulation

Biology 11



• A heart beats about 100,000 times a day and 35 million

times a year.• Every minute, the heart pumps our entire supply of blood

-- about five litres -- through the body.

• In one day, the heart pumps nearly 7200 litres of blood.In a 70-year lifetime, it pumps about 185 million gallons.

• An aorta is almost the diameter of a garden hose, but ittakes ten capillaries to equal the diameter of a strand of human hair.

• There are 100,000 km of blood vessels in each human!

• In ancient times, the heart was given special importance.

The Chinese considered that happiness originated in theheart, and the Egyptians considered the heart to be thesource of intelligence and emotion.

• Heart cells can beat on their own without interventionfrom the brain.

Interesting Facts



• Small unicellular organisms do not

need a circulatory system. Why do

larger organisms need one?

• HINT: Think surface : volume ratio.



The Importance of Circulation

• Unicellular organisms do not need anyspecialized system to transport nutrients,wastes and gases.

• The cells of unicellular and simple

multicellular organisms are never far awayfrom the organism‟s surroundings (from wherenutrients, gases, etc. come from)

• The cells of larger organisms are too far away

for such substances to diffuse to/from all cells.Therefore, a specialized transport system isrequired.

http://www.hpl.hp.com/research/info_theory/AlbertWeb/fullsize/C)%20Denoised%20by%20the%20DUDE,%20residual%20error%20rate=0.0075.gif



Transport in Animals:

Open vs. Closed Systems

• Most animals have evolved specialized systems totransport gases, nutrients and metabolic wastes.

These systems in animals have two essential parts:

1. circulatory fluid (blood)2. a pump (heart or other muscular structure)

• Some animals have blood vessels (optional)

– if vessels are present… closed transport system. Ex: Human

– if absent ………… an open transport system ex.Grasshopper



Circulatory System Overview

• http://www.youtube.com/watch?v=R-

sKZWqsUpw

http://www.youtube.com/watch?v=R-sKZWqsUpw







Funct ions Inc lude • Transport of life sustaining nutrients, O2, hormones

• Transport of wastes such as CO2 and urea.

• Protection from disease (Leukocytes)

• Clotting

• Maintaining constant body temperature.

• Helps with regulation of fluid levels in body.

• General movement of blood through bloodvessels:

heart arteries arterioles capillaries venules

veins heart

BLOOD



What are the components of

Blood?

Blood contains 4 components:

• 55 % Plasma

• 45% Erythrocytes

• <1%Leukocytes

• <1% Platelets

Ratios are maintained!

Solutes ↑, ↑ H2O absorbed

Solutes ↓ , H2O excreted



What is Plasma and what does

it contain?• Plasma is the liquid portion of blood. It is

composed of approximately 90% fluid

along with blood proteins, glucose,

vitamins, minerals, dissolved gases, andwaste products of cell metabolism.



There are 3 protein groups in

the Plasma

• The albumins work together with

inorganic minerals to maintain body fluid

levels by drawing water via osmosis back

into the capillaries

• The globulins assist in protecting the

body from foreign invaders

• The fibrinogens play an important role in

blood clotting.



Components of Blood• Blood cells come from stem cells in bone

marrow.



What is the role of Erythrocytes?• Erythrocytes are red blood cells (RBC) whose job is to

carry oxygen.• Haemoglobin is an iron-containing protein that significantly

increases the ability of the red blood cells to carry oxygen.

• Hemoglobin comes in 2 forms, Oxyhemoglobin when it is

bound to oxygen (bright red), Carbinohemoglobin when itis bound to CO2 (dark red)

• Red blood cells are biconcave in shape which increasestheir surface area for gas exchange by 20 to 30%.

**Your Hematocrit level (when

getting blood-work) is the

percentage of Erythrocytes in

your blood



**Anemia is a condition when you don‟t

have enough Erythrocytes / Hemoglobin**



THINK!

Why would people with low Iron levels in

their diet experience symptoms such as

fatigue and muscle weakness?

Hemoglobin composed of mostly iron .:.

Low Iron means reduced oxygen transportcapacity!



What are Leukocytes?• Leukocytes are white blood cells (WBC), whose

primary function is to protect against infection

• There are different types that perform different

functions; for example Macrophages perform

Phagocytosis on foreign invaders to eliminate themfrom the body

• Humans contain significantly less leukocytes than

erythrocytes

• A ratio of 700 RBC‟s to 1 WBC



What are Platelets?

• Platelets play a crucial

role in blood

clotting. They break

open when they come incontact with the sharp

edge of a broken blood

vessel and release

chemicals which beginthe blood clotting

process



The Human

Circulatory

System



• http://www.youtube.com/watch?feature=pl

ayer_embedded&v=DAXa4eR1s0M#!

http://www.youtube.com/watch?feature=player_embedded&v=DAXa4eR1s0M






Components of The Human Circulatory

System The Heart

– two atria (right and left) (singular = atrium)

– two ventricles (right and left)

– Has valves to prevent backflow

Blood Vessels

– Arteries

– Arterioles

– Capillaries

– Veins

– Venules



REMEMBER

The heart‟s chambersare named as if you are

fac ing someone !

Right Atrium / Ventricle= Left Side of Page

Left Atrium / Ventricle =

Right Side of Page



Circulatory Routes of the Human

Cardiovascular System• The CV system is a closed, one-way

system (blood only flows in onedirection)

• However blood flows in two distinct circuits

Pulmonary Circuit

• path of blood:

• right side the heart lungs (blood picks up O2 and gets rid of CO2) left side of heart.

Systemic Circuit

• path of blood:

• left side of the heart tissues in the body to deliver O2, nutrients, get pick up wastes right side of heart.



TWO kinds: Atrio-ventricular and Semilunar…

Atrio-Ventricular (AV) Valves• each is located between an atrium and a ventricle

• when the ventricles contract, these valves prevent blood fromflowing from the ventricles back into the atria

Tricuspid valve – has three „cusps‟ or flaps that open and close.

– between right atrium and right ventricle

Bicuspid (mitral) valve

– has two „cusps‟ or flaps thatopen and close.

– (AKA mitral valve)

– between left atrium and left

ventricle

l f h



...Valves of the HeartSemilunar Valves

• located in the two major arteries as they

leave the heart• prevent blood flow back into theventricles

• each have a crescent or half-moon(semilunar) shape

Pulmonary Valve – leads to the pulmonary artery

– between right ventricle and pulmonary artery

Aortic Valve

– leads to the aorta

– between left ventricle and aorta

• Cool fact: Ever listen to your heart beat? Itmakes a “lub-dub” sound. As your ventriclescontract, your AV valves close preventing

backflow into atria “lub”. When your ventricles relax, the semilunar valves close

preventing backflow “dub”

• animation: valves in action

http://www.smm.org/heart/heart/pumping.htm

http://www.smm.org/heart/heart/pumping.htm



Heart Valve Pics



Tricuspid Valve

Bicuspid [Mitral]

Valve

Pulmonary Valve

Aortic

Valve

B

A

C

D



Flow of Blood Through the

Heart



C t f Th H Ci l t S t



Components of The Human Circulatory System

Blood Vessels

Arteries: – take blood from heart.

– not always rich in O2 .

– size: 25 mm (aorta) to 0.5 mm.

– branch into smaller arteries called

arterioles (< 0.5 mm). arterioles

contain „smooth‟ muscle that

regulates blood pressure.

– „elastic‟ in nature. they stretch and

„bulge‟ when heart pumps blood

through feel your pulse!



Blood Vessels

Veins:

– take blood to heart – not always low in O2

– branch into smaller veinscalled venules

– the lumens (openings) arelarger than that of arteriesbut walls are thinner.

– depend on contraction of surrounding skeletal muscleto move blood.

– contain valves prevent

backflow of blood.

Look atthe veins

on this

guy!



Valves in Veins Prevent

Backflow



When the valves of the veins

are leaky… varicose veins !



Blood Vessels

Capillaries:

– tiny blood vessels. about 0.008 mm in

diameter, just wide enough for one

red blood cell to pass through.

– one cell thick; makes exchange of

materials between blood and body

cells easy.

– connect arterioles and venuoles

– the total length of all the capillaries in

your body is 1000‟s of kilometres.

Total surface area is nearly 6000 m2.

Why?

– Penetrate almost every tissue in the

body.



Comparison of Blood Vessels



Blood Vessels of a Fetal Pig

CV Word Scramble



CV Word ScrambleSeveral structures of the circulatory system are listed below.Unscramble the terms to describe the flow of blood through the body.Start with "blood from the body". Present your answer as a flow

chart-style graphic organizer.

• Blood from the body

• bicuspid valve

• Superior vena cava

• carbon dioxide• right ventricle

• Inferior vena cava

• pulmonary valve

• Left ventricle

• Oxygen

• Right atrium

• oxygen

• body

• Left atrium

• Pulmonary artery• Tricuspid valve

• Pulmonary veins

• lungs

• Aortic valve

• carbon dioxide

• Aorta

Bl d f thSuperior &



Blood from theBody

Superior &Inferior Vena

CavaRight Atrium Tricuspid Valve

Right VentriclePulmonary Valve Pulmonary Artery

Lungs

Dump CarbonDioxide

Pick up Oxygen Pulmonary Veins Left Atrium

Bicuspid ValveLeft VentricleAortic ValveAorta

Body

Pick up Carbon

Dioxide Dump Oxygen Back to Heart

1 2 3 4

8 7 6 5

9 10 11 12

13141516

17 18 19 20



Locating Heart

Sounds with a

Stethoscope



Conduction System of the Heart• cardiac muscle can contract

without external nerve

stimulation (i.e. messages fromthe brain). The heart can continueto beat for a short time onceremoved from the body

• the heart‟s tempo is set by thesinoatrial node (SA node); a

bundle of specialized nerves. It isoften referred to as the

pacemaker. Its tempo is set toabout 70 bpm (beats per minute).

• the autonomic (automatic) nervous system regulates heartrate but does not initiatecontraction (the SA node does).

It speeds up/slows down the SAnode as needed.



Conduction System of the HeartElectrical Impulse in Heart:

• SA node initiates cardiac cycle. It sends out

an electrical impulse.

• electrical impulse spreads over both atria

causing them to contract

• At the same time, it sends an impulse to theAV node

• impulse is slowly spread through AV node and

then to the Bundle of His (atrioventricular

bundle)

• impulse spreads through both sides of the

septum

• impulse goes to Purkinje Fibres whichstimulate contraction of ventricles!



ECG (Electrocardiogram)

• An ECG can be used to measure the electrical fieldsproduced within the heart. Doctors can analyze such aECG to diagnose heart problems.

P-wave

Atrial

contraction

T-wave

Ventriclesrecover

QRS-wave

Ventricular contraction

Regulation of Heart Rate -



Regulation of Heart Rate -

Autonomic Nervous System (ANS)• Although the heart can beat without nervous intervention, heart rate

must be regulated by the nervous system as conditions change• The ANS is comprised of the sym pathet ic nervous system and the

parasympathet ic nervous system

ANS

Sympathetic

nervous system

Parasympathetic

nervous system

Stimulated by brain in times of

stress (fight or flight ). It makes

heart beat faster. Blood flowincreases.

Stimulated by brain in times of

relaxation. It makes heart beat

slower. Blood flow decreases.

• Tachycardia : When Heart Rate > 100 bpm. This can be caused byexercise or drugs such as caffeine or nicotine.



Regulation of Blood Flow• The Autonomic Nervous System (ANS) maintains

homeostasis automatically .• Pre-Capillary sphincter muscles encircle arterioles before

capillary beds. The ANS can regulate blood flow to tissues by

sending a nerve impulse to these muscles causing them to

contract or relax.

• Contraction of Pre-Capillary sphincter muscles

vasoconstr ic t ion (less blood flow)

• Relaxation of Pre-Capillary sphincter muscles

vasodialat ion (more blood flow)

Wh t i Bl d P ?



What is Blood Pressure?• Blood pressure is the measure of force against

the blood vessel walls

• Measured in the brachial artery (in upper arm). Itis measured in the units “mmHg” (millimetres of

mercury)

• Blood pressure is measured by a device called a

sphygmomanometer (blood pressure cuff)

• Blood pressure has two readings; systole anddiastole.

• Systo le : blood pressure when the ventricles

are contracting.

• Diastole : blood pressure when the ventricles

are relaxed.• Blood pressure varies with age, health, exercise.

A typical resting BP is 120/80 (read as “120 over

80”)

Regulation of Blood Pressure



• It is important to regulate blood pressure.

Low b lood pressure reduces blood flow.

High bloo d pressure weakens arterieswhich may rupture. Consistently high blood

pressure is called hypertension.

• BP is regulated by renal system (kidneys),

nervous system, and by hormones.

Together, physiological changes are madeto raise or lower blood pressure.

• Special sensors called baroreceptors

detect pressure change in the aorta and

carotid artery (in neck). The baroreceptorssend messages to medulla oblongata to

increase/decrease.


regulation of blood pressure

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter21/animation__baroreceptor_reflex_control_of_blood_pressure.html

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter21/animation__baroreceptor_reflex_control_of_blood_pressure.html




If blood pressure is LOW :

• vasoconstr ic t ion : smooth muscle around the blood vesselscontracts, narrowing the lumen of the vessels ...BP

• b lood vo lume : blood volume … BP

• cardiac output : Heart Rate (beats/min) and Stroke Volume (mL per beat) increase… BP

If blood pressure is HIGH :

• vasodi lat ion : smooth muscle around the blood vesselsrelaxes. the blood vessel opens up …BP .

• b lood vo lume : blood volume … BP • cardiac outpu t : Heart Rate and Stoke Volume … BP

measuring blood pressure

i f

http://glencoe.mcgraw-hill.com/sites/0003292010/student_view0/chapter50/animations_and_videos.html

http://glencoe.mcgraw-hill.com/sites/0003292010/student_view0/chapter50/animations_and_videos.html




Cool facts:

• Some people think an alcoholic drink willwarm you up on a cold day. It actually cools

you down! Alcohol causes vasodilation of

blood vessels in skin. This increases blood

flow to skin…heat is lost!

• Alcohol makes some people congested!

Blood vessels in nose dilate nasal

passages close off.



THINK!

• Why does your face turn red and feel

warm when you blush?

biology 11 cadriovascular unit notes

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