Stem cells

Question 1

Cell proliferation:

Answer 1

When cells replicate themselves

Question 2

Cell differentiation:

Answer 2

When unspecialised cells develop characteristics and functions of particular cells

Question 3

How many different cell types can the inner cell mass (stem cells) become?

Answer 3

200+, anything but embryonic cells

Question 4

Totipotent:

Answer 4

Any cell in the human body (200) + embryonic membrane, placenta and umbilical cord

Question 5

Pluripotent:

Answer 5

Can become any cell in the human body, but not the embryonic membrane

Question 6

Multi potent:

Answer 6

Gives rise to types of cells with a specific function, found in adults
Eg, red bone marrow gives rise to RBC

Question 7

What are the three primary germ layers? + examples

Answer 7

Endoderm- epithilium lining of alimentary canal, urinary and gall bladder
Mesoderm- bones, cartilage, blood
Ectoderm- nervous system, teeth enamel, epidermis of skin

Question 8

5 key roles of the placenta:

Answer 8

Endocrine gland- secretes oestrogen + progesterone
Gas exchange 
Waste removal 
Immunity 
Nutrition (glucose, lipids)

Question 9

Foetal development- 3 months

Answer 9

Forelimbs well developed, eyelids closed, outer ear completed, bone marrow formed, blood cells formed in bone marrow, sex distinguishable

Question 10

Foetal development- 4 months

Answer 10

Arms and hands fully shaped, skeleton completed, movement of muscles

Question 11

Foetal development- 5 months

Answer 11

Fine hair covers body, gripping reflexes, more growth

Question 12

Foetal development- 6 months

Answer 12

Respiratory movements, digestive glands begin to function, tooth buds formed, eyebrows/ eyelashes

Question 13

Foetal development- 7 months

Answer 13

Period of greatest growth, all systems functional except respiratory system

Question 14

Foetal development- 8 months

Answer 14

Accumulation of fat beneath skin, growth slows

Question 15

Foetal development- 9 months

Answer 15

Eyes open, nose well for,ed, sucking and grasping reflexes, fine body hair is shed

Question 16

The 5 steps of implantation: (think abcde)

Answer 16

1- fertilisation
2- early cleavage
3- late cleavage
4- blastocyst formation
5- implantation of blastocyst

Question 17

What is blastocyst?

Answer 17

Hollow ball of cells that surround a cavity filled with fluid

Question 18

Why does implantation occur?

Answer 18

So the blastocyst can gain nourishment for growth and development by absorbing nutrients from uterine lining

Question 19

Functions of the placenta: endocrine:

Answer 19

Secretes a number of hormones needed to maintain pregnancy

Question 20

Functions of the placenta: excretory

Answer 20

Transports nitrogenous waste such as urea, Uric acid, ammonia and creatinine from foetal blood or mothers blood (excreted through kidneys)

Question 21

Functions of the placenta: immune

Answer 21

Transports antibodies from mother into foetal blood for immunity

Question 22

Functions of placenta: nutritional

Answer 22

Transports nutrients such as glucose, amino acids, fatty acids, vitamins and minerals from mother to foetus, stores essential nutrients early in pregnancy and releases later

Question 23

Functions of placenta: respiratory

Answer 23

Transports oxygen from mother to foetus and co2 from foetus to mother