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By the end of this section, you will be able to:
  • Identify the anatomical features of a bone
  • Define and list examples of bone markings
  • Describe the histology of bone tissue
  • Compare and contrast compact and spongy bone
  • Identify the structures that compose compact and spongy bone
  • Describe how bones are nourished and innervated

Bone tissue (osseous tissue) differs greatly from other tissues in the body. Bone is hard and many of its functions depend on that characteristic hardness. Later discussions in this chapter will show that bone is also dynamic in that its shape adjusts to accommodate stresses. This section will examine the gross anatomy of bone first and then move on to its histology.

Gross anatomy of bone

The structure of a long bone allows for the best visualization of all of the parts of a bone ( [link] ). A long bone has two parts: the diaphysis    and the epiphysis    . The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone. The hollow region in the diaphysis is called the medullary cavity    , which is filled with yellow marrow. The walls of the diaphysis are composed of dense and hard compact bone    .

Anatomy of a long bone

This illustration depicts an anterior view of the right femur, or thigh bone. The inferior end that connects to the knee is at the bottom of the diagram and the superior end that connects to the hip is at the top of the diagram. The bottom end of the bone contains a smaller lateral bulge and a larger medial bulge. A blue articular cartilage covers the inner half of each bulge as well as the small trench that runs between the bulges. This area of the inferior end of the bone is labeled the distal epiphysis. Above the distal epiphysis is the metaphysis, where the bone tapers from the wide epiphysis into the relatively thin shaft. The entire length of the shaft is the diaphysis. The superior half of the femur is cut away to show its internal contents. The bone is covered with an outer translucent sheet called the periosteum. At the midpoint of the diaphysis, a nutrient artery travels through the periosteum and into the inner layers of the bone. The periosteum surrounds a white cylinder of solid bone labeled compact bone. The cavity at the center of the compact bone is called the medullary cavity. The inner layer of the compact bone that lines the medullary cavity is called the endosteum. Within the diaphysis, the medullary cavity contains a cylinder of yellow bone marrow that is penetrated by the nutrient artery. The superior end of the femur is also connected to the diaphysis by a metaphysis. In this upper metaphysis, the bone gradually widens between the diaphysis and the proximal epiphysis. The proximal epiphysis of the femur is roughly hexagonal in shape. However, the upper right side of the hexagon has a large, protruding knob. The femur connects and rotates within the hip socket at this knob. The knob is covered with a blue colored articular cartilage. The internal anatomy of the upper metaphysis and proximal epiphysis are revealed. The medullary cavity in these regions is filled with the mesh like spongy bone. Red bone marrow occupies the many cavities within the spongy bone. There is a clear, white line separating the spongy bone of the upper metaphysis with that of the proximal epiphysis. This line is labeled the epiphyseal line.
A typical long bone shows the gross anatomical characteristics of bone.

The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled with spongy bone. Red marrow fills the spaces in the spongy bone. Each epiphysis meets the diaphysis at the metaphysis, the narrow area that contains the epiphyseal plate    (growth plate), a layer of hyaline (transparent) cartilage in a growing bone. When the bone stops growing in early adulthood (approximately 18–21 years), the cartilage is replaced by osseous tissue and the epiphyseal plate becomes an epiphyseal line.

The medullary cavity has a delicate membranous lining called the endosteum    (end- = “inside”; oste- = “bone”), where bone growth, repair, and remodeling occur. The outer surface of the bone is covered with a fibrous membrane called the periosteum    (peri - = “around” or “surrounding”). The periosteum contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments also attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints ( [link] ). In this region, the epiphyses are covered with articular cartilage    , a thin layer of cartilage that reduces friction and acts as a shock absorber.

Periosteum and endosteum

The top of this illustration shows an anterior view of the proximal end of the femur. The top image has two zoom in boxes. The left box is situated on the border between the diaphysis and the metaphysis. Its callout magnifies the periosteum on the right side of the femur. The view shows that the periosteum contains an outer fibrous layer composed of yellow fibers. The inner layer of the periosteum is called the cellular layer, which is composed of irregularly shaped cells. The cellular layer gradually shrinks in width as it transitions from the metaphysis to the diaphysis. A small blood vessel runs through both layers and enters the bone. The right zoom in box magnifies the endosteum on the left side of the bone. The box is situated just inferior to the border between the diaphysis and the metaphysic. It calls out the inner edge of the compact bone layer. The magnified view shows concentric circles of dark colored bone matrix. Between the circles are small cavities containing orange, diamond-shaped cells labeled osteocytes. The left edge of the bone matrix is lined with a single layer of flattened cells called the endosteum. There is a large cell, labeled an osteoclast, between two of the endosteum cells. The osteoclast is cutting a depression into the bony matrix under the endosteum. At another part of the endosteum, three smaller osteoblasts are secreting a blue substance that builds up the outermost layer of the bony matrix.
The periosteum forms the outer surface of bone, and the endosteum lines the medullary cavity.

Flat bones, like those of the cranium, consist of a layer of diploë    (spongy bone), lined on either side by a layer of compact bone ( [link] ). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer.

Anatomy of a flat bone

This illustration shows a cross section of a cranial bone, constructed somewhat like a sandwich. The topmost and bottommost layers are the thin, translucent, periosteum. The upper and lower periosteum cover an upper and lower layer of compact bone, respectively. The compact bone is solid, with each layer occupying about one tenth of the thickness of the cranial bone. The majority of the cross section is occupied by the spongy bone, or diploe, sandwiched between the upper and lower compact bone. The spongy bone contains many crisscrossing threads of bone. Dark air spaces occur between the threads, giving the bone a porous appearance, much like that of a sponge or Swiss cheese.
This cross-section of a flat bone shows the spongy bone (diploë) lined on either side by a layer of compact bone.

Questions & Answers

explain general principal of cell communication
Renuka Reply
where the blood is purified .
sameer Reply
where the bone growth occur in endochondral ossification
zhimei Reply
Endochondral ossification happens during emrbyogenesis. All of the bones in the body expect your skull and clavicles are produced through this mechanism. Endochondral ossification is the long process that occurs when hyaline cartilage is replaced by bone (osseous) tissue during fetal development.
Carmelo
except*
Carmelo
hello everyone here is a question what is the physiology of micturition
famuyiwa
@Famuyiwa, I answered that question after I talked about the spleen and kidneys :) Hope it helps.
Carmelo
that is right
mumin
What are the layers of the pancreas?
julie
what is the reason after birth the baby didn't cry
Karthik Reply
because the lung is not yet functioning properly probably due to pulmonary disorder
Ahmed
because ductus arteriosus should have been closing off by that time and expansion of the lungs should make the baby to cry under normal physiological condition
Ahmed
yes that is true the lung is not yet functioning
Hibo
what is the difference between the spleen and the kidney
famuyiwa
@Famuyiwa, the spleen and kidneys are part of two different organ systems. The spleen is a lymphoid organ that cleans blood from pathogens and also breaks down old RBCs.
Carmelo
The kidneys are part of the urinary system. It has several functions such as: filtration of blood from excessive ions and nitrogenous wastes (urea, uric acid, ammonium, creatinine), pH balance of blood, water concentration, regulation of blood pressure, and synthesis of hormones like renin and vit D
Carmelo
?
Kechi
thanks Carmelo
famuyiwa
so what is the physiology of micturition
famuyiwa
hii
sameer
where blood is purified
sameer
hi anyone know where the bone growth in endochondral ossification
zhimei
Micturition involves that the bladder is halfway full causing it to stretch. This will trigger the stretch receptors in the destrusor muscles to fire action potentials to the CNS. As a result, the micturition reflex is activated and sends nerve impulses down to the destrusor muscle to contract.
Carmelo
The internal urethral sphincter will be triggered to relax as well causing the urine to move into the urethra. The micturition reflex is located on the Pons.
Carmelo
micturition center*
Carmelo
what is a cell cycle
GINA Reply
The cell cycle is essentially the life cycle of a cell. In eukaryotic cells, The cell cycle consists of the interphase and mitosis(cellular division).
Carmelo
What is blood
Clare Reply
Blood is composed of plasma and formed elements. Blood plasma is considered extracellular fluid and makes up 55% of blood volume. It contains about 90% water. It also contains nutrients, hormones, gases, ions, proteins, and other molecules. If you have an infection, it might also contain pathogens.
Carmelo
The formed elements are RBCs (45% of blood volume), WBCs and plalets (less than 1% of blood volume) A cool fact is that blood is considered a type of connective tissue since the formed elements of blood comes from mesenchyme stem cells origin.
Carmelo
differences between channel protein and carrier protein in the plasma membrane?
Kumih Reply
does the parietal pleura attached itself to the ribs
Kumih
The main difference is that solutes simply pass through a protein channel, while solutes bind to protein carriers causing a conformational change in the carrier protein and then allows the solute to pass by.
Carmelo
Besides that, both transporters have the same function which is to allow specific solutes in and out of the cell.
Carmelo
The parietal pleura does come in contact with the ribs.
Carmelo
what structure holds the vertebral column in place?
Holly Reply
the ligarmentum flavium
Kumsah
round cushion pads that sit on the between the vertebrae. The intervertebral disc is made up of strong tissue
Kumih
Alimentary canal tissue type
Noob Reply
it consists the oesophagus ,stomach small intestine, large intestine
Kumih
alimentary canal is a type of tissue that consists of mouth, pharynx, oesophagus, stomach, large intestine, small intestine, rectum, and anus
snr
The alimentary canal consists of 4 tunics, and it has all the main tissue types in the body. 1st tunic: Mucosa (simple columnar epithelia) 2nd tunic: Submucosa (dense irregular conn. tissue) 3rd tunic: Muscularis externa (smooth muscle) 4th tunic: Serosa (simple squamous epithelia).
Carmelo
There is also nervous tissue that are present in the muscularis extrena tunic. In the rectum and anus, the mucosal layer contains non keratinized stratified squamous epithelia.
Carmelo
what is epithelial tissue
snr Reply
epithelial tissue is a line in the outer surface of an organism and blood vessels through out the body and inner surface cavities
Kumih
Epithelial tissue is one of the main tissue types on the body. it's main function is to cover and line outer and inner surfaces of organs. For example your skin is epithelial tissue which lines your outer self. The lining of the mucosal layer in your gastrointestinal tract is epithelial tissue.
Carmelo
epithelial tissue is incredibly diverse in function though. It also synthesize and secrets certain products like saliva, hormones, sweat, sebum and mucus.
Carmelo
It also forms structures such as exocrine and endocrine glands, endothelial, and mesothelial membranes as well.
Carmelo
can someone please explain the process lymphatic system
famuyiwa
There are many different types of epithelial tissue and different functions they perform.
Carmelo
@Famuyiwa, the lymphatic organ system contains lymphatic capillaries, vessels, lymph nodes, lymphoid organs and tissues. The lymphatic system is responsible for maintaing blood pressure, filter lymph (activate the immune system), leukopoeiesis, and break down old RBCs.
Carmelo
thanks alot
famuyiwa
welcome, almost forgot, another important function of the lymphatic system is to transports fats inside chylomicrons to the liver and adipose tissue mainly.
Carmelo
This happens after absorption of fats in the enterocytes have occurred and are moved into the latest vessels that lead into lymphatic vessels.
Carmelo
ok
famuyiwa
lacteal*
Carmelo
What is anatomy
Arko Reply
Structures of anatomy
Arko
anatomy is the study of science that deals with how the parts of a body is being structured
snr
anatomy is the study of organisms and the relationship of it's parts
Kumih
tree diagram of the composition of the blood
Poonam Reply
please you said our external hair is dead n non sensational so we the ladies apply cream to it, does it have a negative effect or not?
Abigail Reply
stupiddihedd
Chisom
epithelial tissue connective tissue muscle tissue nervous tissue
Eliham Reply
....
Ruth
Is this a question.. or a statement!!?
Mel
Jesus love us!
Daniel
thank you I needed that!!! praise the lord
Melissa
praise God!
Sherin
lol. it was joke. i am atheist xd
Daniel
so what?
Sherin
Jesus is the only living God.
Sherin
one who find refuge in him will rest with him.
Sherin
isnt this a page to ask for anatomy questions.. not bible study
Mel
Share Jesus without fear all around the world
Sherin
and anywhere you want.
Sherin
ok bible thumper. my ex a preachers daughter was a closet lesbian who f***ed me more times at church then we did hymns
Mel
y'all are the worst hypocrites in the entire world
Mel
that's what you say... but we are living for the our King Jesus not for the world.
Sherin
your king will not save you
Mel
lady you need common sense not jesus
Mel
he's saves me everyday and I do have many testimonies
Sherin
as long as you repent on sundays. y'all are free to sin the rest of the week. but are biggots towards gays and those with a different mindset.
Mel
don't look at anyone else. please clean yourself first
Sherin
lady you are probably a troll
Mel
if you live according to the commandments in Bible, you get saved by Jesus as well
Sherin
I'm not a troll
Sherin
testimonies your kind will say y'all die in his name but dont know his words...
Mel
I'm sharing his word
Sherin
how... amen thats really shows people god exists
Mel
every word in the Bible is in tip of our tongue
Sherin
we live and die for him
Sherin
i think the same. i am atheist because all religions were made for money and authority. they telling us fake stories and scary us.
Daniel
you may have read the bible and may go to church but didnt deny being a biggot
Mel
Jesus do exist and I have experienced it mam
Sherin
not everyone is for money, Daniel
Sherin
again she wont deny shes a biggot
Mel
there are people who are fake in Christianity. I'm not saying there isn't. but there are people who just live for him because they experienced Jesus more in their lives. I will pray for y'all for him to touch you.
Sherin
let him speak to you in Jesus name!
Sherin
but mostly yes. they could do good things too but working in nonreligious organisations. i dont said everyone is bad.
Daniel
I'm not getting any money for telling this you.
Sherin
lady i have gone to church read the bible. and Quran both have truths but you as a whole as in the church are the worst Hippocrits
Mel
find churches that are small in congregation
Sherin
even if they had good intentions they spread bad theories, for example: creationism.
Daniel
all they do is pray
Mel
but wont do anything else
Mel
id love to meet you to see who im talking to from behind a screen who says Ill pray for someone who NEVER ASKED.
Mel
Quran does have truth because they copied it from the Bible. when was Bible written. Things which are happening now are from Bible. Think...when was Bible written? and things happening now from it... so are you saying there's no truth in it?
Sherin
think? they are not the same
Mel
in Quran, it says they have to make other people Muslim or else they have to kill people for their God. is that correct?
Sherin
there are less biggots again you dont deny that. and such nicer people with open arms
Mel
so you haven't read the Bible clearly.
Sherin
read the New Testament and you will figure it out.
Sherin
youll turn away a gay man and welcome a rapist
Mel
while Buddhists and islamics welcome the gays and turn away the phedos
Mel
so you are basically saying that people who worship Jesus are fake people right?
Sherin
i bet you never read the quran ever
Mel
Christianity welcomes everyone, but Church have been taught people come in.
Sherin
omg.... youll try to save rapist before allowing your own blood (child) to live in your homes who comes out gay. or not wanna be a Republican. or a gun holder
Mel
I haven't read it. But in its all hates
Sherin
but they have to change from it.
Sherin
ever person i met who is like you. has a conceal carry. owns a gun. goes to church is republican and doesnt like any races besides there own....
Mel
obviously after knowing his name, they clearly will get away from all the bad thinga
Sherin
my point you believe the bible but wont educate yourself on other beliefs...
Mel
who said that?
Sherin
now tell me if the other assumptions are wrong
Mel
which church or person said that to you?
Sherin
well you wont deny it? so it has to be true.....
Mel
no church saud it. i came from a mostly white town with plenty of racists gun wearing biggots
Mel
they are completely wrong. You think Allah said anywhere in the Quran that "he's coming back soon
Sherin
What's Gun used for? It's for yours or my protection from others right.
Sherin
it's not like you have to kill innocent people.
Sherin
if you or me kill innocent people what will happen?
Sherin
you or me will go to hell only.
Sherin
if someone try to come and fight with you or me. we will take the gun for our protection.
Sherin
allah is always creating and coming back by new life....
Mel
you as a person has no right to say about the quran till you have read it...
Mel
most of the American people have Gun with them. they go to church, they call God, they worship, they do fellowship etc.. for Jesus
Sherin
but again you dont deny your not a racist biggot
Mel
or welcome gays .....
Mel
religion doesn't mean racist.
Sherin
or dont protect rapist... or were you abused and liked it
Mel
I like everyone.
Sherin
rapist shouldn't be doing that. According to Bible it's sin
Sherin
guns shouldnt be owned by those who are not right mentally or ment for harm. but again police use deadly force everyday
Mel
Why does Christian doesn't fight back when they struggle with others?
Sherin
according to the bible we shouldnt wear mixed fabrics....
Mel
But why does Muslims does it?
Sherin
we shouldnt lay with man
Mel
According to Bible gays are sin as well
Sherin
man shouldnt lay with man excuse me
Mel
actually.. they dont
Mel
if you are married, it's okay to lay with a man. because in the Bible it says after marriage, they are one. not 2 anymore
Sherin
but you wouldnt know that since you never studied or educated yourself
Mel
you watch news?
Sherin
How many news I know about hate from Muslims towards Christianity.
Sherin
again your kind would rather protect a rapist who prays than your own kids who hide in the closet as a gay man or woman
Mel
Gun shots around the world done by Muslims towards Christianity in Churches.
Sherin
oh good lord....here we go i watch more news channels than i bet have in a year
Mel
heaven and hell doesnt exist. when we die we end our existence. TOTALY. there is nothing after death. we have only 1 life so dont waste time to pray something whad dont exist, and do some good for other people. we are here and now. everything on the world depends what we do. any god dont do anything
Daniel
and dont get me going on politics or trump lady
Mel
so you know. in America itself, in an year bow many Gun shot happens because of religious hates.
Sherin
who said I'm a trump supporter.
Sherin
I don't support any politics. I only live for Christ.
Sherin
How do you differentiate Haversian canal and Volkmann canal?
Holly Reply
These are differentiated based on location. Haversian canal are present right in the middle of the osteon. the Volkmann canals are located to the sides of Haversian canal and their blood vessels and nerve fibers invade deep into spongy bone in long bones.
Carmelo
thank you
Holly
What are coronal arteries?
julie
The coronary arteries/veins are the group of arteries and veins that supplies the myocardium of the heart.
Carmelo

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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