HUMAN TRANSPORT

TRANSPORT: the life function that involves absorption (taking in) and circulation (moving around) of essential materials to maintain life

All circulatory systems require 3 things:

I. A circulatory fluid to carry stuff (blood)

II. A system of vessels (tubes such as arteries, veins, and capillaries)

III. A pump to push the fluid (heart)

HUMAN CIRCULATORY SYSTEM

contains a series of blood vessels (closed system) which carry a fluid (blood) that contains hemoglobin (carries oxygen)

I. Blood- a complex tissue (a group of similar cells) that is used as a medium (a carrier of stuff) to carry materials throughout the body

A) Plasma

* mostly H2O (about 90%); straw-colored
* carries dissolved salts, nutrients, gases, hormones, proteins, antibodies, platelets, enzymes and molecular wastes

B) Red Blood Cells (Erythrocytes)

* most abundant (numerous) type of cell in the body
* shaped like a BreathSaver (biconcave)
* are about 8 um in diameter
* produced in red bone marrow
* do not have a nuclei and cannot reproduce
* contains HEMOGLOBIN, a red, oxygen-carrying pigment

C) White Blood Cells (Leukocytes)

* used to fight off foreign particles (called antigens) in the body-immune response
* larger but fewer than red blood cells
* can have one or more nuclei
* produced in bone marrow and lymph nodes
* there are 2 main types:

PHAGOCYTES: these white blood cells engulf and destroy bacteria and foreign matter at the site of an infection (puss!)--phagocytosis
LYMPHOCYTES: these white blood cells make antibodies (which are proteins) to fight off antigens--antibodies neutralize antigens


D) Platelets

* these are NOT CELLS, but proteins!
* a component of blood which helps clotting occur (stops bleeding)
* when a blood vessel "breaks" (a cut), these platelets patch up the break through a series of enzyme-controlled reactions

***ICF--Intercellular Fluid--LYMPH***

* fluid from plasma that is found in between all cells
* when it enters the lymphatic system (the other set of pipes), it is known as LYMPH
* helps fight off disease

Human Transport
red blood cells, their true biology story
antibodies--one line of our defenses
the job of platelets, shown with the help of foam peanuts and yarn

II. Blood vessels- the systems of enclosed tubes that carry blood through the body

A) Arteries

* blood vessels that transport blood away from the heart to other parts of the body (A for artery-A for away)
* have thick muscular walls
* these walls throb (or pulse) to help the blood flow through

B) Veins

* blood vessels that transport blood to the heart from different parts of the body
* have thin walls without muscles
* have one way valves that prevent the blood from flowing backwards (V for veins-V for valves)

C) Capillaries

* microscopic blood vessels that connect arteries and veins
* are only one cell thick! red blood cells can only pass through these vessels one cell at a time
* because capillaries are only one cell thick, oxygen and other dissolved nutrients as well as carbon dioxide and other dissolved wastes easily diffuse from the blood to the cells of the body and vice versa!

ALL CELLS OF THE BODY ARE IN CONTACT WITH A CAPILLARY!

THICK ARTERIAL WALLS (blood leaving the heart)
THIN WALLS OF THE VEIN (blood returning to the heart)
SUPER THIN CAPILLARIES (connects the arteries and veins and is the site of material exchange)

and now all together...

*** The Lymphatic System ***
Lymph is a fluid which bathes all the cells of the body. It is also called ICF (Intercellular fluid). This is made up of mostly fluid that escapes from the blood through the walls of the capillaries. Tiny, lymphatic capillaries are found in all tissues of the body. These join to form lymph vessels which are thin walled vessels that also contain valves to prevent backflow. Eventually, all lymph returns to the circulatory system through various ducts that empty into large veins below the neck. In this way, fluid that is lost through the capillary is returned to the blood. At intervals along the lymph vessels, there are bead-like enlargements called lymph nodes. Here, phagocytic white blood cell, some of which are produced in the lymph nodes, remove bacteria and other foreign particles (antigens) from the lymph (ICF). When a lymph nodes enlarges (becomes swollen), it can be an indication of some type of infection.

 

Human Transport
take a look at how the molecules move in capillaries!

III. The Heart- a sectioned muscle that continually pumps blood through the circulatory system

A) General Information
* made up of cardiac (heart) muscle
* contains 4 chambers (sections):

2 ATRIA (ATRIUM): top sections; thinner walls; blood enters the heart here then goes to the ventricles

2 VENTRICLES: bottom sections; thicker walls; blood leaves the heart here

* the blood flows from atria (top) to ventricle (bottom) on each side
* the left side of the heart has oxygenated blood "red blood" and the right side has the deoxygenated blood "blue blood"
* there are vavles in the heart to make sure that blood travels the right direction (A ---> V) that is atria to ventricle--just like artery to vein!!!

* as the heart pumps blood, it creates a blood pressure, this is the pressure on the walls of the arteries as blood flows through them

* when the ventricles contract and squeeze blood out of the heart, it is called the systole (or systolic pressure)
* when the ventricles relax and blood from the atria refill them, it is called the diastole (or diastolic pressure)

Normal Blood Pressure = 120 (systolic) / 80 (diastolic)

B) How The Blood Travels
1) vena cava- blood enters the heart through this main vein
2) right atrium- blood enters the upper right chamber (upper left in pictures!)

3) right ventricle- blood passes through the one-way atrioventricular valve to the right ventricle
4) pulmonary arteries- blood leaves the heart to get oxygen from the lungs

5) lungs- oxygen enters the blood and carbon dioxide leaves the blood
6) pulmonary veins- carries oxygenated blood to the heart
7) left atrium- blood from the lungs returns to the heart

8) left ventricle- blood passes through another one-way valve to the left ventricle
9) aorta- blood travels to the rest of the body through this main artery

C) Different Types of Circulation

* pulmonary circulation- the flow of blood to and from the lungs
* coronary circulation- the flow of blood to the muscles of the heart and back
* systematic circulation- the flow of blood to and from most body systems (except the lungs and heart)

Human Transport
a nice review of the heart system...once open, choose the appropriate button
THE HUMAN HEART
okay, so if you like a little blood-and-guts, then this open heart surgery is for you
record and analyze various ECGs; a fun game for students; advanced for Regents class.
a longer video that shows all the highlights of the human circulatory system
see how the heart's natural pacemaker works
review the pathway that blood takes through the heart in this interactive

IV. Human Immune System- which is linked with the circulatory system; how the body defends against disease

A) phagocytes- "eat" antigens (foreign particles) by phagocytosis

B) lymphocytes- produce antibodies that neutralize antigens...the IMMUNE RESPONSE:

1) an antigen (foreign particle) enters the body
2) lymphocytes "see" this (receptor molecules) and make antibodies
3) antibodies link up with the antigen and neutralize them so they are no longer harmful

4) antibodies stick around for a LONG TIME--only get chicken pox once

* there are 2 types of immunity

i) active immunity--when antibodies are produced by the organism from an actual infection (antigens) or by a vaccination (which is when weakened or dead antigens are introduced to start the production of antibodies)

ii) passive immunity--when already formed antibodies are given to an organism's body (as in a mother's breastmilk)

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ALLERGIES- when the body reacts to harmless chemicals (called allergens)

ex. pollen, dust, dander, insect bites, foods, drugs, molds

if you are allergic to something, your body produces histamines which cause an allergic response (runny nose, swollen eyes, sneezing, coughing, hives, etc...)


V. Blood Typing- determining the compatibility of different antigens found on blood cells

there are 2 types of blood antigens:
A and B
there are four major blood types:
A, B, AB, and O

* the blood types depend on what type of antigen (protein) is on the blood cells
* also, the blood will carry antibodies of the opposite type of the blood
* if you have the ANTI-A ANTIBODY and you are given blood with the A ANTIGEN, (in this case, either type A or type AB) they will react and clump the blood! THAT'S BAD!
* if you have the ANTI-B ANTIBODY and you are given blood with the B ANTIGEN, (in this case, either type B or type AB) they will react and clump the blood! THAT'S ALSO BAD!

* if you have type O, you can donate blood to anyone because your blood has no antigens on it!
* if you have type AB blood, you can receive blood from anyone because you have no antibodies for antigen A or B!

***Organ/Tissue Transplants***
when an organ is transplanted from one person to another, it has to match up, otherwise the new body will "reject" the organ...this can be fatal!

 

Human Transport
another cool Flash game--this one is called "Immune System Defender"; learn how the different parts of the immune system work as you fight off an infection
these three clips all show the human immune system at work
play this 'video' game from NOVA showing how our immune system works
see how vaccines were first tested--yup, how science was done back in the day

these two video clips feature penicillin, how it works and the history of its discovery

check out this NOVA link showing how some vaccines are made
correctly match up blood types for transfusions or watch the consequences!

VI. Malfunctions of the Circulatory System

A) Cardiovascular Disease- affects both the heart and the blood vessels

1) High Blood Pressure (Hypertension)-

* most common cardiovascular disease
* there is increased pressure on the arterial walls
* can weaken arterial walls and heart muscle
causes: stress, diet, hereditary reasons, smoking, aging

2) Heart Attack (Cardiac Arrest)-there are two main types:

a) ANGINA PECTORIS--when the heart muscle is damaged because the coronary arteries are narrowed resulting in the heart muscle not getting enough oxygen

b) CORONARY THROMBOSIS--when the coronary artery is blocked resulting in the heart muscle not getting enough oxygen and stops beating

B) Blood Conditions

1) Anemia-when the blood cannot carry a "full amount of oxygen"

possible causes:
* reduced number of red blood cells
* reduced amount of hemoglobin

2) Leukemia-also known as "blood cancer"

* a disease of the bone marrow
* the body produces a large number of non-functional white blood cells

C) Human Immunodeficieny Virus (HIV)

* a virus that exists in bodily fluids
* the virus attacks the immune system (specifically--certain white blood cells)
* when the white blood cell count drops below a certain level, you have AIDS (Acquired Immune Deficiency Syndrome)

Human Transport
keep that blood in the brain, or you'll pass out, like Bill Nye!
what is AIDS?
some of the interesting history of the HIV virus and AIDS