Cells To Tissues

Question 1

Describe epithelial tissue

Answer 1

• absorption, secretion, protection
• sheets of cells held together by basement membrane
• No blood supply. Rely on diffusion for O2 and nutrients

Question 2

What are the criteria for classifying epithelia?

Answer 2

1. LAYERS- one=simple more=stratified
2. SHAPE- flat=squamous cuboid columnar
3. SPECIALISATIONS- eg. Cilia microvilli keratin

Question 3

What’s the function of simple squamous epithelium?

Answer 3

Lines alveoli- thinnest possible surface for gas exchange

Question 4

What’s the function of cuboidal epithelium?

Answer 4

Lines ducts

Eg. Kidney tubules

Question 5

What’s the function of columnar epithelium?

Answer 5

Large surface for absorption
May have microvilli
Eg. Gut

Question 6

Describe the epithelium lining the respiratory tract

Answer 6

• Pseudostratified ciliated columnar epithelium
• Goblet cells secrete mucus
• Cilia help move dust etc.

Question 7

What’s the function of transitional epithelium?

Answer 7

Stretches easily

Found in bladder and parts of urinary tract

Question 8

What’s the function of stratified squamous epithelium?

Answer 8

• Found where surfaces suffer friction/abrasion
• Eg. Tongue and skin
• Can thicken due to abrasion, forming corns and callouses/nodules on vocal cords(folds) if voice overused

Question 9

Describe skin epithelium

Answer 9

Stratified squamous plus a layer of dead cells and keratin

Question 10

Describe smooth muscle

Answer 10

Single cells
Single nucleus
Not obviously striated
Not under voluntary control
Long, slow contraction, slow to tire
• Eg. Walls of gut, urinary system, blood vessels, respiratory system, skin, endocrine system

Question 11

Describe striated (skeletal) muscle

Answer 11

Fibres containing multiple nuclei
Clearly striated
Voluntary/reflex movement
Fast contraction
• Eg. Skeletal muscles, diaphragm, upper part of oesophagus

Question 12

Describe cardiac muscle

Answer 12

Cells contain single nucleus
Cells linked by intercalated discs- allow fast conduction
Not under voluntary control
Striated
• Heart wall

Question 13

Describe loose connective tissue

Answer 13

• Thin flexible elastin fibres, thicker stronger collagen, fibroblast cells- synthesise the fibres
• Proportions tissues can vary
• Some secrete a matrix- surrounds the cells
• Adipose tissue- loose connective tissue with fat cells

Question 14

Describe bone and cartilage

Answer 14

Cells
fibres (mainly collagen)
Matrix- proteoglycans and calcium hydroxyapatite in bone

Question 15

What are the two ways bone can form?

Answer 15

• Endochondral bone- replaces cartilage
Eg. Limbs, vertebrae, skull base

• Intramembranous bone- forms directly in membranes/skin
Eg. Skull

Question 16

What is ossification?

Answer 16

Cartilage forming bone

Question 17

Where does cartilage remain in adults?

Answer 17

Joints
Ears
Nose
Respiratory system

Question 18

What are the three types of cartilage?

Answer 18

Hyaline- joints

Elastic- extra elastin fibres- flexible

Fibrocartilage- extra layers of collagen fibres- intervertebral discs

Question 19

Describe a ligament

Answer 19

Join bones together
High in elastin
Connective tissue

Question 20

Describe a tendon

Answer 20

Join bones to muscles
High in collagen
Connective tissue

Question 21

Describe the knee menisci

Answer 21

Fibrocartilage

Knee also has hyaline cartilage

Question 22

What causes osteoarthritis?

Answer 22

When knee cartilage is rubbed away, extra bone is produced.