Download 7th Grade Science

7th Grade Science
Chapter 7 Notes
The Circulatory System
7.1 – Circulation
Cardiovascular system – includes the heart, arteries, veins, & capillaries
“cardio” – means heart
“vascular” – means vessel (like indoor plumbing)
Heart – made up of 4 chambers
- 2 atria and 2 ventricle
- valves separate the chambers to help direct flow
o 1 – Tricuspid valve – right atrium
o 2 – pulmonary (semilunar) valve – right ventricle
o 3 – mitral valve - left atrium
o 4 – aortic (semilunar) valve – left ventricle
Heart flow:
- Blood (deoxygenated) comes to the heart thru the vena cava
o Superior & inferior vein
- Enters the right atrium & is pumped to the right ventricle
- Right ventricle pumps blood to pulmonary artery to the lungs
- Lungs give O2 for blood to pick up
- Blood comes back from lungs to heart thru pulmonary veins
- Pulmonary veins bring blood to heart thru left atrium
o Oxygenated blood
- Left atrium pumps blood to the left ventricle
- Left ventricle pumps blood to the aorta
- Aorta disperses blood to the rest of the body
Diffusion – higher concentration to lower concentration until equilibrium is reached
- occurs between blood & body cells
- exchanges nutrients, O2 , & waste products
- capillaries connect arteries to veins & the body cells so that the blood used
(deoxygenated & full of wastes) will go to veins & refreshed blood (from
arteries) will get to the cells
Types of Circulation
Pulmonary
From heart to lungs
& back to the heart
Coronary
Blood movement in the
tissues of the heart
Systemic
Blood from heart to the rest
of the body & back
Blood Vessels
Veins
Brings all blood to the heart
heart
Arteries
Carries blood away from the
Pressure is lower
Has a valve to keep one way flow
Higher pressure
Gives us our heart beat (blood
Pressure)
Both are connected by capillaries
Blood pressure – blood exerting a force on the walls of the vessels
- highest in arteries
- normal range from 65-80 beats per min
7.2 Blood
Functions of the blood – is a tissue
- Blood carries O2 from lungs to body cells & gets rid of COs from body cells
- Picks up waste products from cells & delivers to kidneys
- Transports nutrients from digestive tract to body cells
- blood fights infections
Makes up 8% of body
Amt of blood in adults equals about 5 – 1L bottles
If blood drops below 8%, your body goes into shock
Parts of Blood
Plasma – liquid part of blood-mostly water
o contains nutrients & oxygen
o makes up more than half the volume of blood
Red Blood cells – have no nucleus
o Contains hemoglobin
o Acts as a chemical that can carry oxygen and carbon dioxide
o In 1 mm3 – contains 5,000,000 red blood cells
o Life span is 4 months
o Produced in bond marrow
 Particularly in femur and humerus
o Reproduce @ 2-3 million/sec
White Blood Cells – makes up to 5000 to 10000 count in blood
o job is to fight bacteria, viruses, and other foreign substances
o When detects a foreign substance, white blood cell count will increase
o Life span from a few days to months
o They attach and absorb the foreign body
Platelets – help with blood clotting
o contain 400.000 in drop of blood
o life span of 5-9 days
Blood clotting – platelets make your blood clot & forms a natural bandage
-Fibrin – threadlike fibers form a sticky net
- hemophiliac – genetic disease that lacks clotting factors
Blood types – A, B, AB, & O
Antigens – each type has a chemical identifying tag
Antibodies – specific proteins that destroy or neutralize foreign substances
- located in the plasma
Rh factor – give your blood +/- + , if Rh marker is present
- - , if Rh marker is not present
- Inherited
- Cannot be mixed
Anemia – Too few red blood cells
- makes it harder for tissues to receive O2
- can result from disease, sickness, severe injury
Leukemia – white blood cells rapidly reproduce immature cells
- do not function properly
- can cause death
- typically need a bone marrow transplant
7.3 Lymphatic system
Lymphatic system – collects fluid from body and tissue spaces and returns it to
The blood thru a system of lymph capillaries and larger lymph
Vessels
- contains cells that help your body defend itself against disease-causing
organisms
- blood passes nutrients and o2 to cells
- some becomes part of tissue fluid in-between cells
- the lymph vessels collects and moves those molecules
Organs – Lymph nodes, Lymph, Lymphocytes
- Lymph nodes
o Filter out microorganisms and foreign materials
o Lymphocytes transports these organisms to the node
o At sign of infection, over production of lymphocytes are found in
nodes
o Makes glands tender to touch
- Lymph
o Water (most of it), dissolved substances like nutrients and proteins
and lymphocytes
- Lymphocytes
o Type of white blood cell
o Is not pumped by heart – relies on muscular contractions of
skeletal system
Diseases
HIV – Human Immunodeficiency Virus
- attacks and destroys Helper T cells (type of lymphocyte)
- Helper T Cells
o Produce antibodies to fight infections
o Less T cells, less fight against pathogens
o Can lead to death