Tissues and homeostatis

Question 1

Describe the order of organization

Answer 1

atomic
molecular
organelle
cell
tissue
organ
organ system
organism

Question 2

What are the 4 tissue types?

Answer 2

Muscular, connective, epithelial and nervous

Question 3

Describe the structure, importance and function of epithelial tissue

Answer 3

There are 2 types of epithelial tissue (stratified and simple)
Stratified refers to many layers whereas simple refers to a single layer of cells. Epithelial tissue is involved in protection, filtration, excretion, secretion, and absorption. It covers the organs and lines the blood vessels. 2 forms of epithelium glandular (secretion) and covering and lining (BV’s)

Question 4

What are the 4 shapes of the epithelial tissue

Answer 4

Columnar, cuboidal and squamous, these tissues all have differently shaped nuclei and are all attached to basement membranes

Question 5

Describe squamous epithelium

Answer 5

It is a single thin permeable flat layer of cells, normally found in places where diffusion is required e.g., alveoli. It contains disc-shaped nuclei & sparse cytoplasm. involved in filtration e.g., kidney, secretion. epithelium supported by a basement membrane

Question 6

Describe cuboidal epithelium

Answer 6

it is cube-shaped with a large central spherical nucleus, involved in secretion and filtration (kidneys), found in kidney tubules and ovaries

Question 7

Describe columnar epithelium

Answer 7

Highly specialized cells with oval nuclei, tall cells, found with goblet cells in the trachea, which secrete mucus, also found in digestive tract

Question 8

Describe pseudostratified columnar epithelial cells

Answer 8

These are single layers of cells that differ in height, and so the nuclei are at different levels to the adjacent cell, which may contain goblets cells and cilia. Involved in mucus secretion e.g., in digestion, the ciliated type propels the mucus in a direction.

Question 9

Describe the role of connective tissue

Answer 9

It’s main function is to support and bind the organs e.g., cartilage found in lungs

Question 10

What are the functions of connective tissue?

Answer 10

heat production, transport, binding of organs, immune protection, physical protection, support, storage, movement

Question 11

Describe the common characteristics of connective tissue

Answer 11

Connective tissue is the most abundant in the body, it has an extracellular matrix, which enables it to bear weight

Question 12

Give examples of connective tissues

Answer 12

Blood, cartilage, adipose tissue, elastic tissue, bone tissue etc

Question 13

What are the 3 main tissue types of connective tissue?

Answer 13

Areolar, adipose and dense connective tissue

Question 14

Describe areolar tissue

Answer 14

it has elastin and collagen fibres with a loose arrangement, it provides support, connects organs and tissues, and acts as cushioning and packing between organs. found beneath the skin surrounding organs and blood vessels, defends against infections

Question 15

Describe adipose tissue

Answer 15

This is fat tissue, involved in insulation, cushioning of organs & protection. Brown adipose in infants produces heat, contains lots of fatty acids, and is used for energy, 90% of mass in cells is adipose, richly supplied with nerve tissue

Question 16

Describe dense connective tissue

Answer 16

a dense tissue containing lots of collage fibres, irregular pattern, very strong and contain fibroblast nuclei. it creates fibrous coverings around organs and joints for protection

Question 17

Difference between clasts and blasts cells

Answer 17

Clast cells breakdown connective tissue
blast cells are mitotically active and secrete fiber and matrix

Question 18

What is a lacuna

Answer 18

a space/cavity

Question 19

what are the 3 types of cartilage?

Answer 19

hyaline cartilage, fibrocartilage and elastic cartilage

Question 20

Describe hyaline cartilage

Answer 20

Most abundant in the body
involves in structural support and flexibility
Has spherical chondrocytes
Only fibre is collagen fibres
It covers the end of most movable joints (articular cartilage)
Connects the ribs to sternum (costal cartilage) aids in respiring
Supports the nose (nasal cartilages) and the respiratory system (respiratory cartilage)
Contain perichondrium which surrounds cartilage

Question 21

Describe elastic cartilage

Answer 21

Contains more elastic fibres than hyaline cartilage
Able to stretch and recoil e.g., in blood vessels, prevents bursting from high BP
Are involved in repeated bending movements

Found only in external ear and epiglottis

Question 22

Describe fibrocartilage

Answer 22

very fibrous lots of thick collagen fiber bundles, less matrix, fibers spread in all directions, resistant to impact, shock absorbent, found in knees and pubic bone
Consist of parallel rows of chondrocytes which alternate with thick collagen fibres

Question 23

What are collagen fibres?

Answer 23

made of the protein collagen, assemble and cross-link together, and bundle together to form thick collagen fibres, due to linkage they are extremely strong, and tough and can resist being pulled apart

Question 24

What are elastic fibres?

Answer 24

long & thin elastic fibres form branching networks, contain protein elastin, enabling stretch and recoil, found where elasticity is needed e.g., lungs and blood vessels

Question 25

What is ground substance?

Answer 25

Known as the matrix contains proteins which trap water to make it a gel-like substance, site of protein synthesis and movement of organelles

Question 26

Define Homeostasis

Answer 26

the ability to maintain an optimum internal environment within narrow limits, it is a dynamic equilibrium which is adapts due to changes in external environments

Question 27

Examples of homeostatis

Answer 27

Temperature control- controlled by the hypothalamus, thermoreceptors on skin’s surface can detect a stimulus (temp change) and sends signals to the hypothalamus for it to coordinate a response to bring body temperature back to optimum condition

Question 28

Define negative feedback and give and example

Answer 28

Negative feedback is the most common homeostatic mechanism it prevents further deviation from optimum conditions e.g., sugar levels in the blood, need to be regulated, if too high, insulin is released storing excess glucose as fat, if too low glucagon is released to breakdown glycogen and release glucose into the bloodstream

Question 29

Define positive feedback

Answer 29

This is when the response to the stimulus involves a greater deviation from set point, it is positive as it moves in the same direction and not a loop
e.g., in labour, contractions are intensified by oxytocin as labour continues more oxytocin is released in increasing frequency and power of contractions. This continues until the baby is born

Question 30

What is a cell

Answer 30

smallest functional unit of an organism

Question 31

Purpose of nucleus

Answer 31

Holds DNA, controls activities of the cell

Question 32

Purpose of plasma membrane

Answer 32

acts as a barrier, contains bulk of cell, involved in endo and exocytosis, controls what enters and exits cell

Question 33

Cytoplasm function

Answer 33

gel-like substance, serves a site for enzyme reactions

Question 34

What is chromatin

Answer 34

contains DNA, encodes the proteins, found in the nucleus

Question 35

what is the nucleolus

Answer 35

involved in synthesis of ribosomes

Question 36

What are ribosomes

Answer 36

responsible for making proteins through transcription and translation, ribosomes read RNA, cause AA’s to bulk together and build proteins

Question 37

What is RER

Answer 37

site of protein production,

Question 38

what is the golgi apparatus>

Answer 38

site where protein is modified and packaged, becomes enzymes or glycoproteins

Question 39

what is a vesicle

Answer 39

responsible for transporting proteins, can be exported outside of the cell via exocytosis

Question 40

Cytoskeleton function

Answer 40

anchors organelles in place, provides a network in which vesicles travel along

Question 41

SER

Answer 41

smooth endoplasmic reticulum involved in detoxfication, synthesis and packaging of lipids