Tissues And Organs Flashcards
Order of cellular structures
Cell -> Tissue -> Organs -> Organ System
How is the ileum adapted for absorption?
Many folds in the inner surface
Many villi that are present on the folded surface of the wall
Many microvilli on the cell surface membranes of columnar epithelial cells
Structures of the ileum from top to bottom
Mucosa
Muscularis mucosa
Submucosa
Muscularis externa
Serosa
State things found in the ileum
Goblet cells
Columnar epithelium
Network of blood capillaries
Lymphatic vessel
Crypt of Lieberkühn
Paneth cells ( at base of crypt )
(Venule
Circular muscle
Longitudinal muscle)
What is the function of the Columanr epithelium
Layer of cells that line the intestine. They have microvilli on their free surface, digestive enzymes are bound to the membrane of the microvilli providing a huge surface area for digestion and the absorption of its products. Many methods of transport are used, mitochondria present for active transport
Cells of the epithelium are short lived
What is the function of goblet cells
Secrete mucus to protect the epithelium from the action of digestive enzymes whilst also lubricating the lining as solid material passes along
What is the function of villi
Fingerlike projections to increase the surface area for absorption
Villi contain blood capillaries which amino acids and monosaccharides are absorbed
Contains lacteals into which fats are absorbed
What is the function of crypts of lieberkühn
They’re intestinal glands found at the base of the villi
The cells lining the bottom of the crypts are in a state of continuous division
After several days the cells are pushed to the tips of the villi where they are sloughed off.
Paneth cells are present to defend the the actively dividing cells against microbes in the small intestine
What is the function of the Muscularis mucosa
Muscle fibres contract to cause movement of the villi, improves contact with the products of digestion
What is the function of the submucosa
Contains blood vessels, including venules of the hepatic portal vein and lymphatic vessels, supported by connective tissue.
What is the function of Muscularis externa
Consists of circular muscle and longitudinal muscle. Contractions of longitudinal muscle causes pendulum movement of the gut while contraction of the circular muscle may result in local constrictions. Coordinated contractions of ten circular muscle push food along the gut by peristalsis
What is the function of serosa
Outer layer of connective tissue serves to protect and support the gut
State the structure of the leaf from top the bottom
Waxy cuticle
Upper epidermis
Palisade mesophyll
Spongy mesophyll
Lower epidermis
Cuticle
State strucres found within the leaf
Xylem
Phloem
Air spaces
Guard cells
Stoma
( Xylem Phloem are grouped called a vascular bundle ( vein ) )
What is the function of the upper epidermis
Cells lack chloroplasts since their role is protective, they secrete a waxy cuticle that provides waterproofing and reduces water loss
What is the function of the palisade mesophyll
The palisade layer has layers of tightly packed cells with abundant chloroplasts, adapted for maximal light absorption, this is the main photosynthetic region of the leaf
What is the function of the xylem vessels
Xylem vessels supply the leaf with water and inorganic ions
What is the function of phloem sieve tubes
Transport sucrose away from the leaf
What is the function of the lower epidermis
Cells lack chloroplasts. The cuticle secreted on the lower surface is thinner than on the upper surface since it is not exposed to the sun directly.
What is the function of the stomata
Lower epidermis contains numerous, allows for gas exchange, they also allow water vapour to diffuse easily out of the leaf. Each stoma is surrounded by a pair of guard cells which close it at night so water lost by transpiration is minimised
