Chapter 7: Skeletal System

Name the small chambers that house bone cells.

Lacunae

What bones belong to the axial skeleton?

Sacrum, skull, ribs, vertebrae

What roles do sex hormones play in bone growth?

They stimulate growth at epiphyseal plate and therefore long bone growth & they stimulate closure of the epiphyseal plate and therefore stop long bone growth.

Which hormone stimulates osetoblasts at the epiphyseal plate?

Thyroxine

In order to breakdown bone, osteoclasts secrete ____ to dissolve the inorganic components and use ____ to digest the organic components.

acid ; lysosomal enzymes

The periosteum is located ____ and plays a role in ____ .

around bones ; bone growth and repair

What are four major functions of a bone, an organ of the skeletal system?

attachment for muscles, storage of inorganic salts, blood cell formation, support and protection

which root word means "bud"

blast

how many distinct layers form the epiphyseal plate?

4

Giantism is caused by

; excess human growth hormone in childhood.

The extracellular matrix of bone tissue is largely composed of what two components?

Collagen and inorganic salts

4. Zone of calcified cartilage

Composed of dead cartilage cells encased in bone matrix

How does a long bone grow in width?

Deposit of new bone under the periosteum of the diaphysis

T or F. Bones of athletes are usually thinner and weaker than those of non athletes.

False, exercise stimulates bones to grow and thicken.

When does a long bone stop growing in length?

when the epiphyseal plate ossify completely

Bone marrow that stores fat

yellow

What is an example of a long bone?

femur

Red bone marrow's color is due to the pigment ___ found in the red blood cells.

hemoglobin

Calcitonin is released when blood calcium levels are ___. This hormone stimulates ___ to build bone, storing excess calcium.

high ; osteoblasts.

Chemicals that are secreted by endocrine glands called ______ play a critical role in the homeostatic balance of bone matrix by regulating blood ion levels of calcium.

hormones

What bones are found in the upper limb?

humerus, ulna, radius

In enchondral ossification, as masses of ____ cartilage breaks down, ____ deposits bone in the spaces created.

hyaline ; osteoblasts.

The extracellular matrix of bone tissue includes collagen as well as abundant inorganic mineral salts called :

hydroxyapatite

Where is marrow found in the bone?

in the spaces of spongy bone

Root word "intra" means ____ while the root work "inter" means

inside ; between

The process of bone formation from membrane like layers of connective tissue is called :

intramembranous ossification

1. Zone of resting cartilage

layer closest to the epiphysis

parathyroid hormone is released when blood calcium levels are ___. This hormone stimulates ___ to break down bone releasing calcium into the blood.

low ; osteoclasts

During inter membranous ossification, a layer of ___ becomes the periosteum on the outside of the bone.

mesenchyme

three factors that affect bone development, growth and repair.

nutrition, physical exercise, hormones

The first region of bone formation, where cartilage slowly breaks down and spongy bone forms in the place. Its called a primary ____ center.

ossification

vitamin A

osteoblast and osteoclast activity

Thyroxine stimulates ___ activity, which aids in bone development and growth.

osteoblasts

During ossification ___ deposit bony matrix around themselves, ultimately surrounding themselves with bone. Once surrounded by bone, these cells are called ___ .

osteoblasts ; osteocytes

what is true about intramembranous ossification?

osteoblasts deposit new bone along blood vessels, it occurs between flat sheets of connective tissue, skull bones are formed via intramembranous ossification.

three proteins found in bone :

osteocalcin, collagen, osteonectin

The ---- are the cells that dissolve in the inorganic components of the calcified bone matrix.

osteoclasts

Bone remodeling occurs continually as ___ reabsorb bone tissue and ___ replace the bone. The total bone remains nearly constant.

osteoclasts ; osteoblasts

Cells called _____ dissolve bony matrix, white cells called _____ deposit new matrix.

osteoclasts ; osteoblasts

Parathyroid hormone stimulates bone cells called _____ which break down bone.

osteoclasts.

Mature bone cells are called _________

osteocytes

What are bone cells called?

osteocytes

The lamellae in compact bone are arranged in cylinder-shaped units called ___

osteons

A disorder of the bones that is similar to osteoporosis, only milder, is ____

osteopenia

In _______ bone mass declines, bones easily fracture and may spontaneously break because they no longer can support body weight.

osteoporosis

Which hormone stimulates osteoclast activity?

parathyroid hormone

Which hormone stimulates osteoclasts activity?

parathyroid hormone

Horizontal, or transverse tubes that connect central canals are _____ canals.

perforating

in the intremembranous ossification, mesenchyme tissue that persists outside the developing bone gives rise to the ___

periosteum

Deficit of growth hormone is childhood results in what disorder?

pituitary dwarfism

What are some functions of bone?

protect body structure, house blood cell forming tissue, store inorganic salts.

The formation of blood cells occurs in the ___ bone marrow found in bone.

red

The two types of bone marrow are ____ and ___

red & yellow

During bone marrow transplant, cells are retrieved from __ bone marrow located in ____ bone of a donor.

red ; spongy

layers of epiphyseal plate in order from closest to the epiphysis :

resting, proliferating, hypertrophic, calcified

The thoracic cage consists of twelve pairs of ___ and one ___

ribs ; sternum

2. Zone of proliferating cartilage

rows of young cells, undergoing mitosis

Indicate the bones of the appendicular skeleton

scapula, tarsals, patella, fibula

In a closed bone fracture, the ___ is unbroken. In a compound fracture it is broken.

skin

How might a bone marrow transplant recipient get cells necessary for blood cell formation?

stem cells separated out of donor's blood, retrieval of red marrow cells from donor's spongy bone, stem cells from umbilical cord of a newborn.

Sex hormones stimulate formation of bone tissue during puberty; they also stimulate ossification of the epiphyseal plate and therefore they ______ bone lengthening.

stop

What are trabeculae?

thin, bony plates in spongy bone

The osteocytes is spongy bones are arranged within the branching bone plates called :

trabeculae

The bones that form the spinal column, or back bone are called

vertebrae

Axial skeleton / appendicular skeleton

vertebrae, frontal bone, ribs / carpals, femur scapula

UV radiation striking skin is a step in activating ___ which then plays a role in absorption and availability of ___ for use in forming bone matrix.

vitamin D ; calcium

What is rickets?

vitamin D deficiency in children causing deformed bones

Growth hormone stimulates cell division at the ___

epiphyseal plate

What is the name of the structure located between the primary and secondary ossification centers?

epiphyseal plate

The hormone __ has a stronger effect than ____ on the epiphyseal plate, causing it to close more quickly. This explains the discrepancy in height between male and female adults.

estrogen ; testosterone

A disorder called acromegaly is caused by

excess growth hormone secretion in adults.

T or F. Once bone is built in childhood, it never changes.

false

As endochondral ossification begins, where does bone tissue first begin to replace hyaline cartilage?

center of the diaphysis

Which bones compose a pectoral girdle ?

clavicle and scapula

vitamin C

collagen synthesis

Most bones of the body are :

endochondral bones

The membrane lining the medullary cavity is called the __

endosteum

What is a function of the skeletal system

House blood producing cells

Place the steps of endochondral ossification in order as they would occur.

Hyaline cartilage model forms cartilage tissue breaks down osteoblasts form spongy then compact bone osteoblasts become osteocytes

what is a fracture

broken bone

What is a component of bone matrix and also participates in muscle cell contradiction nerve cell conduction and blood clot formation?

calcium

Vitamin D

calcium absorption

Osteocytes exchange substances w nearby cells through cellular processes that lie in grooves called the __

canaliculi

3. Zone of hypertrophic cartilage

cartilage cells enlarging while osteoblasts deposit bone matrix

Compact bone has a ____ matrix, while the matrix of spongy bone is ____.

dense ; formed into trabeculae.

A long bone has an expanded portion at each and called an epiphysis and a shaft called the _____

diaphysis

During endochondral ossiciation, a primary ossification center appeals in the ____ whereas secondary ossification center appears in the ____ .

diaphysis ; epiphysis