Lecture Test 2: 19-21 Flashcards
(34 cards)
What is lymph transport propelled by?
Pulsations of nearby arteries!
Contractions of smooth muscle in the walls of the lymphatics.
One way system, Lymph flows toward the heart!
Functions of the Lymphatic system?
- ) Returns interstitial fluid and leaked plasma proteins back to the blood.
- ) W/ lymphoid organs and tissues, they provide structural basis of immune system.
What are the lymphoid organs?
- ) Tonsils
- ) Thymus
- ) Spleen
- ) Peyer’s Patches
- ) Appendix
- ) lymph nodes
What are the 2 basic functions of lymph nodes? (The principal lymphoid organ)
Filtration and
Immune system activation!
Function of the spleen, and when is it the most active?
Largest lymph organ.
Site of lymphocyte proliferation and immune surveillance and response.
Cleanses the blood of aged cells, platelets and debris.
What are the functions of the Thymus and when is it most active?
Size changes with age.
Functions strictly in T lymphocyte maturation.
Most active during childhood.
What is the simplest lymphoid organ?
Tonsils. Named according to location. Palatine Lingual Pharyngeal Tubal
They gather and remove any pathogens entering the pharynx in food or inhaled air.
What are Peyer’s Patches?
Clusters of lymphoid follicles. In the wall of the distal portion of the small intestine.
Destroy bacteria preventing them from breaching the intestinal wall.
(Similar structures in the appendix)
MALT ?
=Mucosa-Associated Lymphoid Tissues. Largest collections of MALT: Tonsils Peyer's patches appendix Lymphoid nodules
Protects the digestive and respiratory systems from foreign matter.
Appendix functions and relationship what other lymphatic organs?
First part of large intestines and contains high concentration of lymphoid follicles.
Like Peyer’s patches it is in ideal position;
1) to destroy bacteria before they break through wall
2) generate many “memory” lymphocytes for long term immunity.
Distribution of lymphatic vessels:
The right lymphatic duct.
Drains lymph from the right arm
and right side of the upper body.
Distribution of lymphatic vessels:
Thoracic duct.
Receives lymph from the rest of the body.
These ducts empty into the blood vascular system at the inter-jugular and subclavian veins
Hassalls corpuscles are found in the thymus (inner medulla). Which cells mature in this corpuscles and what is its function?
T lymphocytes.
Help prevent auto immune disease!
Circulation of lymph nodes:
Efferent lymphatic vessels
Lymph Exits the node via this vessel
Fewer of these causing flow of lymph to stagnate (slow down) allowing lymphocytes and macrophages time to carry out functions.
Circulation in the lymph nodes:
Afferent lymphatic vessels
Lymph enters the node via these vessels.
Circulation in the lymph nodes?
3 steps
- Enters via Afferent lymphatic vessels
- Travels through large subcapsular sinus.
- exits the node via efferent vessels
*Fewer efferent vessels to allow functions to carry out! ( slow things down)
- What is Blood pressure (BP)?
Force per unit area exerted on the wall on a blood vessel.
Expressed in mm and Hg
- Percentage of distribution in blood;
Systemic arteries and arterioles %?
Veins and venules %?
15%
And
60%
- Percentage of distribution of blood:
Pulmonary blood vessels %?
Heart %?
Capillaries %?
12%
8%
5%
- What is resistance (peripheral resistance) ?
- Opposition to flow
- measure of the amount of friction blood encounters
- generally encountered in the peripheral systemic circulation.
- Three important sources of resistance?
- Blood viscosity. “Stickiness”
- Blood vessel length (longer the greater resistance)
- Blood vessel diameter (varies inversely if radius is doubled then resis. Is decreased by 1/16th )
- Systemic pressure
- highest in the aorta
- declines throughout the pathway
- is Omm Hg in the right atrium
- Regarding systemic BP where do the steepest drops occur?
The arterioles
How do we maintain BP?
Cooperation of the heart, blood vessels and kidneys along with supervision by the brain.
