T1 Anatomy

Question 1

When does bone development begin and end?

Answer 1

begins week 8

finishes at 20 years

Question 2

Where is bone derived from?

Answer 2

the paraxial and lateral plate mesoderm

Question 3

What are the two types of ossification?

Answer 3

Intramembranous

Endochondral

Question 4

Where does Intramembranous Ossification begin?

Answer 4

in the foetal period where connective tissue is slowly replaced by bone

Question 5

What happens during Intramembranous Ossification?

Answer 5

Direct mineralisation of connective tissue by mesenchyme

Question 6

How does Intramembranous Ossification occur?

Answer 6

Cells divide and condense around capillary network from the primary ossification centre
Grows radially, finally fusing together replacing the connective tissue
Connective tissue that remains penetrated by blood cells and undifferentiated mesenchyme gives rise to bone marrow (hollow)

Question 7

What are three examples of bones generated by Intramembranous Ossification?

Answer 7

skull
mandible
clavicle

Question 8

In Endochondral Ossification what are the cartilaginous templates made from?

Answer 8

mesenchyme

Question 9

When does Endochondral Ossification finish?

Answer 9

6 - 8 weeks

the whole set of cartilage models are made in the embryo

Question 10

What happens to the cartilaginous templates once they have been made?

Answer 10

osteogenesis - the template is slowly replaced by bone
Different ossification centres emerge, a primary one in the diaphysis and secondary ones in the epiphysis
Initially a bone collar is produced and from here the primary centre develops

Question 11

Where is the Growth Plate located?

Answer 11

between the diaphysis and the epiphysis

Question 12

What happens at week 9 in developing bone?

Answer 12

the developing bone is penetrated by blood vessels

Question 13

What is bone maintenance regulated by?

Answer 13

calcium
phosphorous
vitamin A
vitamin C
vitamin D

Question 14

What is the role of vitamin A?

Answer 14

essential for bone remodelling

Question 15

What is the role of vitamin C?

Answer 15

essential for connective tissue

Question 16

What is the role of vitamin D?

Answer 16

essential for calcium absorption

Question 17

What is responsible for controlling bone development?

Answer 17

endocrine activity such as the parathyroid hormone, growth hormone

Question 18

What is the earliest sign of subclinical vitamin D deficiency?

Answer 18

craniotabes

Question 19

What is the role of osteoblasts?

Answer 19

to form the bone (b for building)

to synthesize the organic components

Question 20

What are the organic components of the bone?

Answer 20

collagen
proteoglycans
glycoprotein

Question 21

Where are osteoblasts located?

Answer 21

on the surface of bone
side by side
in a way that resembles simple squamous epithelium

Question 22

Where is parathyroid hormone secreted from?

Answer 22

from four parathyroid glands in the neck

Question 23

What is the function of parathyroid hormone?

Answer 23

to stimulate the release of calcium from large calcium stores in the bones into the bloodstream

Question 24

Which areas of the body does parathyroid hormone affect?

Answer 24

kidneys
bones
intestine

Question 25

What happens when calcium stores are released from the bones into the blood by parathyroid hormone?

Answer 25

increased bone destruction | decreased formation of new bone

Question 26

How does osteoblast maturation occur?

Answer 26

As bone is formed, some osteoblasts become trapped within the matrix they become stuck mature into osteocytes

Question 27

What is the role of osteoclasts?

Answer 27

to eat bone - reabsorb and recycle it

Question 28

What is compact bone covered by?

Answer 28

the periosteum

Question 29

What is the haversian canal in the centre made up of?

Answer 29

lamella | the vascular and nerve supply

Question 30

What are the outer layers of the ovum through which the sperm must penetrate?

Answer 30

the Corona radiate | the Zona pellucida

Question 31

What does the yolk sac contain?

Answer 31

nutrients that supply the embryo before the placenta functions

Question 32

Which cavity develops from within the epiblast at the beginning of week 2?

Answer 32

the amniotic cavity

Question 33

How does the amniotic cavity develop?

Answer 33

the inner cell mass of the epiblast differentiates into epiblast and hypoblast within the epiblast, the amniotic cavity develops the epiblasts that line the cavity become amnioblasts

Question 34

Which two layers form the bilaminar embryonic disc?

Answer 34

epiblast | hypoblast

Question 35

Why does apposition occur?

Answer 35

to ensure that the embryo is still in contact

Question 36

What happens during apposition?

Answer 36

moves itself around and works itself out until the embryonic pole is in contact with the uterine wall

Question 37

What is the function of HCG?

Answer 37

helps to maintain the uterus in its state | helps to maintain the placenta

Question 38

In which weeks does folding occur?

Answer 38

By week 4 | the flat disc has to fold into 2 directions

Question 39

What is the epicardium made of?

Answer 39

loose connective tissue | a high percentage of fat cells

Question 40

What is the function of the Tunica intima?

Answer 40

it reduces friction for blood flow

Question 41

What is the function of the Tunica media?

Answer 41

controls the size and shape of the artery

Question 42

What is the function of the Tunica externa?

Answer 42

connects arteries to the surrounding structures

Question 43

What is the function of the Large Elastic Arteries?

Answer 43

accommodates surges in blood

Question 44

Which factors aid the return of blood to the heart against gravity?

Answer 44

Valves Arteriovenous pump Musculovenous pump Respiratory pump

Question 45

What are the speeds for myelinated nerve fibres compared to those for unmyelinated fibres?

Answer 45

myelinated - up to 120m/s | unmyelinated - less than 1.5m/s

Question 46

What is the difference between directions for afferent and efferent axons?

Answer 46

afferent - towards the CNS | efferent - away from the CNS

Question 47

What are the functions of Astrocytes?

Answer 47

they provide structural support to the NS in embryos, form scaffolding for migrating neurons to move up and down during development supply nutrients to neurons help to maintain ionic environment they uptake NTs help to repair the NS by forming glial scars contribute to the blood brain barrier

Question 48

Which nutrients do astrocytes supply to neurons and why?

Answer 48

glucose lactate important for memory storage

Question 49

What is the function of oligodendrocytes?

Answer 49

to produces myelin for multiple axons

Question 50

What is the main type of neuroglia in the Peripheral NS?

Answer 50

Schwann cells