Lecture 7 - Capillaries & Lymphatics

Question 1

Capillaries

Answer 1

site of exchange between blood and tissues

Question 2

Capillaries function demands

Answer 2

• very thin walls
• large cross sectional area of capillary bed. (much slower blood flow)
• slow & smooth blood flow

Question 3

Capillary structure 3 types

Answer 3

Continuous (most widespread)
Fenestrated (leaky)
Sinusoidal (very leaky)

Question 4

The structure of capillaries varies according to

Answer 4

rate of exchange needed, and how controlled the

exchange must be.

Question 5

Continuous capillary (diametre)

Answer 5

8-10μm

Skeletal & cardiac muscle

Question 6

Fenestrated capillary (diametre, found where)

Answer 6

8-10μm

Glomerulus, Kidney, small intestine.

Question 7

Sinusoidal capillary (diametre, found where)

Answer 7

30-40μm diameter

Liver sinusoids

Question 8

continuous (movement of substances)

Answer 8

Lipid soluble substances (diffusion through membrane)

Water soluble substances (through intercellular clefts)

Large substances (via vesicles or caveolae)

Question 9

Sinusoidal and fenestrated (movement of substances)

difference between continuous.

Answer 9

Water soluble substances (through fenestrations & intercellular clefts)

Lipid soluble substances (diffusion through membrane)

Large substances (via vesicles or caveolae)

Question 10

Lymph vascular system

Answer 10

An open entry drainage system

porous blind ending capillaries

Question 11

Lymph vascular system functions

Answer 11

Drains excess fluid and plasma proteins from tissue and returns them into the blood.

Filters foreign material from the lymph

Screen lymph for foreign antigens and responds by releasing antibodies and activated immune cells

Absorbs fat from intestine and transports to blood

Question 12

Lymphatic vessels structure

Answer 12

Start as large, blind ending capillaries.

From small intestine, a special group of lymphatic
vessels called lacteals drain fat-laden lymph into a collecting vessel called the cisterna chyli.

Larger (thin wall) collecting vessels have numerous valves to prevent backflow.

Question 13

Lymph vessels

Answer 13

Thin walled
no RBCS (clear fluid)
Valves (2 leaflets)
Low pressure

Question 14

Lacteals

Answer 14

Group of lymphatic vessels from small intestine

Drain fat laden lymph (fluid) into collecting vessel (cisterna chyli)

Question 15

Cisterna chyli

Answer 15

Milk jug

Question 16

Endothelial cells of lymph vascular system

Answer 16

Form flat like connections

Makes ends of the blind ending capillaries porous

Allows fluid to easily come between the endothelial cells and drain

Question 17

Lymph valve

Answer 17

Face towards the heart

Back towards the body centre

Prevent backflow

Question 18

Drainage of 2 body regions

Answer 18

Left side and below diaphragm

Right side of face neck, chest, upper limb.

Question 19

Left side and below diaphragm

Lymph drainage channels

Answer 19

Lymphatic collecting vessels (Drains through series)

Thoracic duct (drains back to lymph channel) joins with

Entrance of thoracic duct into left subclavian vein (left side of face and neck joins to single channel. Fluid drained. Close to right atrium.)

Question 20

Right side of face neck, chest, upper limb.

Drains to

Answer 20

right subclavian vein

Question 21

Cluster of lymph nodes

Answer 21

Cervical nodes
Axillary nodes
Inguinal nodes

Question 22

Inguinal nodes

Answer 22

Groin

Question 23

Axillary nodes

Answer 23

Armpit

Question 24

Cervical nodes

Answer 24

Neck

Question 25

Lymph nodes

Answer 25

Act as part of immune surveillance

Matrix of fibres that suspend a lot of immune cells (eg B cells sit and if encounter antigen they’ll become activated and produce antibodies against foreign antigen)

Question 26

afferent lymphatics

Answer 26

Bring lymph from periphery drains through lymph nodes

Question 27

Efferent lymphatics

Answer 27

Takes lymph and find a subclavian vein and drain into the blood vascular system.