AN120: CNS & Endocrine Flashcards
What are the 2 parts of the circulatory system
- CVS
- lymphatic system
the drainage system consists of lymphatic tissues & lymphatic vessels
What are lymphatics
Lymphatics are thin-walled and difficult to recognize. They are lined with endothelium.
1. lymph capillaries: blind-ended which unite to form the medium-sized lymphatic vessel.
2. lymph vessels: larger & collecting in nature. They possess valves & smooth muscles
How does the lymph travel in vessels?
These lymph vessels drain into regional lymph nodes.
What do lymph nodes do?
They engulf foreign & unwanted material
What happens to lymph after it is filtered in the regional lymph nodes?
return back to large veins in neck, close to the heart.
Where are lymphatics found?
- dermis of skin
- serous membrane
- mucous membrane
- glands
Where are lymphatics not found?
- brain & spinal cord
- Aveoli of lungs
- Epidermis of skin
- inner ear
- cornea
- cartilage & bone
- bone marrow
What are the thinnest vessels in the body?
Lymph vessel; they have the thinnest walls
What are lymph nodes?
- bean-like
- periodic interruption of the course of lymphatic collecting vessels
- have a cortex & medulla
What is the function of lymph nodes?
- receive lymph from afferent vessels & discharge via efferent lymphatics
- as microscopic microbial filter against: bacteria, tumor cells, & cell debris
- cleans lymph so that it returns to circulation
What are regional lymph nodes & where are they found?
Can be single or grouped and are particularly at the root of the limbs: example: axillary & inguinal lymph nodes. Also in:
- mediastinum of chest
- posterior abdonimal wall
- mesentries
- in the neck
When do lymph nodes become enlarged & matted together?
During diseases, like:
- severe infection
- metastases
- lymphoma
- lymph node aggregation causing edema
What causes lymph node aggregation?
obstruction of lymphatic vessels and/or cessation of lymph flow
this leads to edema
What are the 2 major lymphatic trunks?
- Rt lymphatic duct: drains right upper limb & right side of head, neck & chest
- Thoracic duct: drains both lower limbs, abdomen, left upper limb, & left side of head, neck, & chest
What is the lymphatic system?
- part of circulatory & immune system
formed of:
1. lymphoid organs
2. network of lymphatic vessels
3. clear fluid called lymph
What is lymph?
Filtered plasma
- plasma that is not reabsorbed back to blood vessels
What are properties of lymphatic vessels?
- thin wall
- wider
- beaded appearance due to valves
- blind-ended
- mechanism of lymph return resembles vein
- low pressure
What are some lymphatic organs?
main one: lymph nodes
2. spleen
3. thymus
4. tonsils
5. peyer’s patches (wall of GIT)
What is the function of the lymphatic system?
- anatomical function: drains tissue fluids
- carries absorbed fatty lipids from GIT to thoracic duct to jugulo-subclavian junction
- immune mechanism: engulfs bacteria & foreign materials while producing lymphocytes
What is the jugulo-subclavian junction?
the venous angle between the internal jugular & subclavian veins
