APP 5 Flashcards
What are lymphatic vessels
A system of blind ended vessels that sit between the arterial and venous system and take back the 15% of the plasma that leaves the capillaries that the venules don’t take back
What are the 3 main components of the fluid that comes out of the capillaries to bathe the cells
Nutrients, oxygen, water
What % of the fluid that comes out of the capillaries gets back to the heart via the lymph vessels?
15%
How does the rest get back to the heart?
Via the venules and veins
Roughly how many lymph nodes are there?
600
Why can large molecules and fats get into lymph vessels but not capillaries?
Because the gaps in the lymph vessel walls are bigger and overlap
Where does the lymph system drain back into the cardiovascular system?
Right & Left subclavian veins
Which subclavian vein drains all the left and part of the right sides of the body?
Left
What are the two ‘pumps’ that help get lymph fluid back up to the heart?
Skeletal pump & respiratory pump
Where are pluripotent stem cells found?
Bone marrow
Which kind of cells are ‘educated’ in the thymus gland?
T cells
Why do nodes swell when you get an infection?
B & T cells multiply
What does the spleen contain?
Red Blood Cells
White Blood Cells
Connective Tissue
What are the tonsils?
Masses of wbcs
What are the 3 main functions of the lymphatic system?
Drainage - 15% of plasma that leaves the capillaries
Transport dietary lipids ADEK and fat soluable vitamins
Immune response
What are the 2 types of Resistance to Disease (Immunity)?
Specific (Adaptive) Non specific (Innate)
What are the 2 main types of white blood cells involved in specific immunity?
B & T Cells
What are the first and second lines of defense in innate immunity?
Preventing things entering the body
Dealing with them after entry
What are interferons and what do they do?
Proteins produced by wbc’s that destroy viruses
What are the 4 signs of inflammation?
Redness
Heat
Pain
Swelling
Why is fever a ‘useful’ response to pathogen invasion ie what effect is it supposed to have?
It raises the temperature of the host body to disrupt the pathogen’s homeostasis
How do white blood cells recognise invaders ?
From the alien molecules on their cell surfaces
What are molecules that generate an immune response called?
Antigens
What are self molecules?
Molecules that all your cells produce that are unique to you
What are the molecules that B cells make called, and how else could you describe them?
They are called Antibodies and can be described as ‘guided missiles’
What’s one way of describing how T cells attack antigens?
Cell to cell combat
What is an allergic reaction?
When a person is over-reactive to an antigen to which most people are tolerant – it may produce an inappropriate immune reaction
What is the endocrine system made up of?
Clusters of epithelial cells that secrete hormones (messenger molecules)
What is the endocrine system for, and how does it do what it does?
To maintain homeostasis -
the messenger molecules make cells do things that keep conditions in the body relatively constant when things around are changing
Why don’t all cells respond to all hormones?
Because only certain cells have receptors for certain hormones
What happens when hormones reach the target tissue cells?
They change what those cells are doing
Which other system, besides the endocrine system, maintains homeostasis?
Nervous system (esp Autonomic NS)
What are the differences between the way the nervous and endocrine systems work?
Neurotransmitters act very locally, very quickly for a very short time
Hormones act over a wide area, work more slowly, and last for a long time
What 3 types of stimulus can make glands secrete hormones?
Nervous signals
Chemical changes in blood
Other hormones
How is the secretion of most hormones controlled, and what is the one exception to this?
Negative feedback, oxytosin
Which two major systems does the hypothalamus control?
Nervous system and Endocrine system
