Skeletal System

Question 1

Many _______ and all _______ possess exoskeletons.

Answer 1

invertebrates, arthropods

Question 2

An ______ is an external skeleton

Answer 2

exoskeleton

Question 3

Vertebrates contain an _________ on the inside.

Answer 3

endoskeleton

Question 4

An endoskeleton can be divided into the _____ skeleton (core bones) and the _________ skeleton (appendages).

Answer 4

axial
appendicular

Question 5

Types of bones in the endoskeleton

Answer 5

Long bones
Short bones
Flat bones
Sesamoid bones
Irregular bones

Question 6

What are long bones made of?

Answer 6

Made of cortical bone (compact) and pockets of cancellous bone (spongy).

Question 7

What important features do long bones have?

Answer 7

EMDME
Epiphysis
Medullary cavity
Diaphysis
Metaphysis
Epiphyseal plate

Question 8

Epiphysis?
Forms what w/ other bones?
What important marrow does it contain?

Answer 8

END of a long bone
Forms joints with other bones
Contains red bone marrow for hematopoiesis (blood cell synthesis)

Question 9

Diaphysis?
Located where?

Answer 9

Long hollow shaft in CENTER of bone

Question 10

Medullary cavity?
Located where?
What important marrow does it contain?

Answer 10

Located within the diaphysis
Contains red AND yellow bone marrow (area of fat storage).

Question 11

Metaphysis?
Located where?

Answer 11

Similar to epiphysis
Found between the medullary cavity & epiphyseal plates.

Question 12

Epiphyseal plate?
Located where?
Made out of what?
Lengthens what?

Answer 12

“Growth plate”
Located between epiphysis & metaphysis
Made out of hyaline cartilage
Lengthens diaphysis through growth & ossification

Question 13

Short bones provide _____

Answer 13

support

Question 14

Flat bones provide _____

Answer 14

protection

Question 15

Sesamoid bones are found within _______ to help ______

Answer 15

tendons, muscles

Question 16

Cortical bone? Function?
Inner or outer layer of bone?

Answer 16

Dense outer layer of bone that supports the weight of our bodies

Question 17

What microstructures is cortical bone made of?

Answer 17

Osteons
Haversian canals
Lamellae
Lacunae
Canaliculi
Volkmann’s canals

Question 18

Osteons
Composed of what?
Also known as what?

Answer 18

Cortical bone’s functional unit, Composed of tiny multi-layered cylinders
Known as haversian systems (contain a haversian canal in center)

Question 19

Haversian canals
Contain what?

Answer 19

‘tubes’ that contain blood vessels for nutrient supply

Question 21

Lamellae

Answer 21

layers of the osteon

Question 21

Lacunae
Hold what?
Interconnect through what?

Answer 21

small spaces between lamellae
Hold bone cells
Interconnect through canaliculi

Question 22

Canaliculi
Connect what?

Answer 22

small channels that connect
lacunae and the haversian canal

Question 23

Volkmann’s canals
Connect what?

Answer 23

connect Haversian canals to the periosteum

Question 24

Cancellous bone?
Dense or spongy?
Soaks up what?

Answer 24

Spongy inner layer of bone
Soaks up red bone marrow via a web of trabeculae (connective tissue that supports cancellous bone)

Question 25

Resorption is bone _____

Answer 25

LOSS

Question 26

Ossification is bone ______

Answer 26

FORMATION

Question 27

What cells are involved in bone remodeling?

Answer 27

Osteoprogenitors Osteoblasts Osteocytes Osteoclasts

Question 28

Osteoprogenitors Differentiate into what?

Answer 28

immature precursor cells that differentiate into osteoblasts

Question 29

Osteoblasts Function? Mature into what?

Answer 29

**BUILD** bone by secreting proteins & utilizing blood calcium. Mature into osteocytes

Question 30

Osteocytes Live where?

Answer 30

live in **lacunae** in osteons to maintain bone

Question 31

Osteoclasts Function? Derived from what?

Answer 31

**EAT & RESORB** bone Releases calcium & phosphate back into the blood Derived from monocytes.

Question 32

# **mechanisms of bone remodeling** Parathyroid hormone function? Secreted by what?

Answer 32

**Increases** blood calcium levels by stimulating osteoclasts & depressing osteoblasts Secreted by the parathyroid gland.

Question 33

# **mechanisms of bone remodeling** Vitamin D function? Activated by what?

Answer 33

**Increases** blood calcium levels by raising calcium absorption Activated by PTH but provides negative feedback on PTH production.

Question 34

# **mechanisms of bone remodeling** Calcitonin function? Secreted by what?

Answer 34

**Decreases** blood calcium levels by depressing osteoclasts, allowing osteoblasts to build bone without competition Secreted by parafollicular cells (C cells) of the thyroid gland. - Calci**TON**in (tone it down)

Question 35

______ is the organic component of bone containing many proteins

Answer 35

Osteoid

Question 36

What gives the bone tensile strength?

Answer 36

Collagen

Question 37

_______ is the inorganic mineral component of bone that gives the bone density and strength.

Answer 37

Hydroxyapatite

Question 38

# Embryonic ossification Endochondral ossification Created indirectly or directly where? Mainly for what bones? Explain the process What is created?

Answer 38

Bone is created indirectly through a cartilage model Mainly for long bones The cartilage model calcifies during fetal development Ossification centers & long bone features are created

Question 39

# Embryonic ossification Intramembranous ossification Created indirectly or directly where? Mainly for what bones? Explain the process What bone is created?

Answer 39

Bone is created directly within fibrous membranes Mainly for flat bones Osteoblasts start by secreting osteoid, which hardens and houses osteocytes. Cortical bone is created

Question 40

What are the two types of embryonic ossification?

Answer 40

1. Intramembranous ossification 2. Endochondral ossification

Question 41

Types of connective tissue (there's 3)

Answer 41

1. Fibrous connective tissue 2. Cartilage 3. Joints

Question 42

Fibrous connective tissue is maintained and repaired by ________.

Answer 42

fibroblasts

Question 43

What makes up fibrous conn. tissue?

Answer 43

Tendons Ligaments Periosteum Endosteum

Question 44

Tendons connect ______ to ________.

Answer 44

muscle to bone

Question 45

Ligaments connect ______ to ________.

Answer 45

bone to bone

Question 46

Periosteum Membrane covers what? What layers does it have? specify what they have

Answer 46

Covers cortical bone Outer fibrous layer (vascularized) Inner layer (collagen for attachment to cortical bone)

Question 47

Endosteum Membrane located where?

Answer 47

membrane located between cortical & cancellous bone.

Question 48

Cartilage is ______ and is NOT ________.

Answer 48

avascular, not innervated

Question 49

What builds cartilage?

Answer 49

Chondroblasts

Question 50

3 types of cartilage

Answer 50

Hyaline cartilage Fibrous cartilage Elastic cartilage

Question 51

Hyaline cartilage Flexibility? Provides what to joints?

Answer 51

slightly flexible Important in providing support and stability to joints.

Question 52

Fibrous cartilage Flexibility? Found where?

Answer 52

high rigidity & resists tension Found in intervertebral discs

Question 53

Elastic cartilage Flexibility? Found where?

Answer 53

highly flexible Found in ears & epiglottis.

Answer 54

highly flexible and found in ears and epiglottis.

Question 55

Chondroblasts build cartilage by secreting ______ and ______.

Answer 55

collagen and elastin

Question 56

Joints are ______ and _______. They are found ______ bones

Answer 56

vascularized, innervated, between

Question 57

3 Types of joints

Answer 57

Synarthroses Amphiarthroses Diarthroses

Question 58

Synarthroses Type of joint? How do they move?

Answer 58

Dense, fibrous joints Do NOT move

Question 59

Amphiarthroses Type of joint? How do they move?

Answer 59

Cartilaginous joints Partially move

Question 60

Diarthroses Type of joint? How do they move? Contain what kind of cartilage?

Answer 60

Synovial joint Fully move Typically contain hyaline cartilage