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Synthesis of vitamin d

This illustration resembles a flow chart. It begins with the sun shining on a silhouette of a man. One arrow leads from the sun to the man’s skin, stating that Vitamin D is manufactured in the skin after the absorption of sunlight. Another arrow points into the man’s mouth and states that Vitamin D is ingested through food and supplements, absorbed by the intestines, and carried to the liver via the bloodstream. A call out of the liver states that, in the liver, Vitamin D turns into 25 (OH) D, also known as calcidiol, the primary form of circulating Vitamin D. Another callout of the right kidney states that, in the kidneys, Vitamin D is transformed into 1 25 OH (D2). This is also known as calcitriol, a biologically active form of Vitamin D. The synthesis of Vitamin D facilitates calcium absorption from the small intestine, calcium re-absorption from the kidneys, and the rebuilding of bone tissue.
Sunlight is one source of vitamin D.

Other nutrients

Vitamin K also supports bone mineralization and may have a synergistic role with vitamin D in the regulation of bone growth. Green leafy vegetables are a good source of vitamin K.

The minerals magnesium and fluoride may also play a role in supporting bone health. While magnesium is only found in trace amounts in the human body, more than 60 percent of it is in the skeleton, suggesting it plays a role in the structure of bone. Fluoride can displace the hydroxyl group in bone’s hydroxyapatite crystals and form fluorapatite. Similar to its effect on dental enamel, fluorapatite helps stabilize and strengthen bone mineral. Fluoride can also enter spaces within hydroxyapatite crystals, thus increasing their density.

Omega-3 fatty acids have long been known to reduce inflammation in various parts of the body. Inflammation can interfere with the function of osteoblasts, so consuming omega-3 fatty acids, in the diet or in supplements, may also help enhance production of new osseous tissue. [link] summarizes the role of nutrients in bone health.

Nutrients and Bone Health
Nutrient Role in bone health
Calcium Needed to make calcium phosphate and calcium carbonate, which form the hydroxyapatite crystals that give bone its hardness
Vitamin D Needed for calcium absorption
Vitamin K Supports bone mineralization; may have synergistic effect with vitamin D
Magnesium Structural component of bone
Fluoride Structural component of bone
Omega-3 fatty acids Reduces inflammation that may interfere with osteoblast function

Hormones and bone tissue

The endocrine system produces and secretes hormones, many of which interact with the skeletal system. These hormones are involved in controlling bone growth, maintaining bone once it is formed, and remodeling it.

Hormones that influence osteoblasts and/or maintain the matrix

Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth in several ways. It triggers chondrocyte proliferation in epiphyseal plates, resulting in the increasing length of long bones. GH also increases calcium retention, which enhances mineralization, and stimulates osteoblastic activity, which improves bone density.

GH is not alone in stimulating bone growth and maintaining osseous tissue. Thyroxine, a hormone secreted by the thyroid gland promotes osteoblastic activity and the synthesis of bone matrix. During puberty, the sex hormones (estrogen in girls, testosterone in boys) also come into play. They too promote osteoblastic activity and production of bone matrix, and in addition, are responsible for the growth spurt that often occurs during adolescence. They also promote the conversion of the epiphyseal plate to the epiphyseal line (i.e., cartilage to its bony remnant), thus bringing an end to the longitudinal growth of bones. Additionally, calcitriol, the active form of vitamin D, is produced by the kidneys and stimulates the absorption of calcium and phosphate from the digestive tract.

Questions & Answers

what is anatomy
Gifty Reply
is the study of body structure
Amos
What are some of first questions are expected in anatomy and physiology course
Milner Reply
what is pacemaker
mekfira
its a device that is put into the heart to make sure it beats properly
Michelle
which of the following is the epithelial tissue that lines the interior of blood vessels?
Firomsa Reply
endothelial tissues
Osaki
Endothelial tissue
mabast
why are the questions only 3
Chisom Reply
you too can ask
Addo
what is the treatment of herpes simplex virus?
riad Reply
the long bone with two primary center's of ossification for shaft is ________
Aarambam
medulla
Addo
good
Ravi
ha moj ha
Hani
doctor and nurse
Ravi
y 're the questions only 3
Chisom
women are much likely to be pregnant at which stage?
Fatoumatta Reply
There are only six days during any cycle when a woman can get pregnant - the five days leading up to ovulation and the 24 hours after ovulation. This is because sperm can live for up to 5 days in a woman's body, and the ovum lives for only 12-24 hours.
THE
right
Adil
does this apply to women close to menopose
Kuria
what's reason the reason for BP growing ?
Adil
when after they have intercourse
AJ
what is andropause
William Reply
It's the men version of menopause!
Catia
The testosterone levels decrease
Catia
what would happen if the sugar lever drops below the normal level
Marvin Reply
If our blood sugar drops below 70 mg/dL, we may have symptoms, such as feeling tired, weak, or shaky, become confused or drowsy or even lose consciousness and possibly die.
Dhanya
symptoms of hypoglycemia include: shakiness, dizziness, headache, confusion, rapid pulse rate, sweating, Hunger, etc.
EMERIBE
you right
Khubaib
You become dizzy and weak
evans
Is there any way to disable this chat feature or at least mute notifications? Also, does every textbook app from this creator have the chat function?
Atone Reply
I don't think you can disable chat and yes it is on every app
AJ
what is homeostasis
Nikky Reply
what is respiratory
Nikky
Respiratory is breathing
Atone
respiration is an exchange of gases (O2 & CO2) between the body and outside environment.
joey
homeostasis is internal balance.
Ali
Respiratory is system where the body takes in oxygen n releases carbondioxide
Hassan
respiratory system is a system where exhalation and inhalation takes place
Kom
1)inhalation: active diaphragm & external intercoastal muscles 2)exhalation: passive (allow muscle group to relax)
Shoukat
mantaince of body is called homeostasis
Komal
hi komal
Khubaib
how are you komal?
Khubaib
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Komal
hey nikki
Khubaib
hii komal
Rinku
where you from kamal?
Khubaib
nice meet you
Rinku
oye rinku kya ha yahan kya kar rha ha
Khubaib
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Komal
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Khubaib
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Rinku
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Khubaib
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Antony
waw komal
Rinku
yar rinku kahan se ho ap
Khubaib
I am from dausa,Rajasthan
Rinku
yar hum to pakistan se hain humy baat karny do
Khubaib
hoe r u alll
SARFARAJ
komal jha?
Khubaib
answer me please...What is basic concept or Acidosis?
Khalid
hiii komal
SARFARAJ
al hamd.o.lillah muslim
Khubaib
or aap
Khubaib
Allah ka shukr ha
SARFARAJ
aby tu b india chala ja un ko zarorat ha foji logon ki
Khubaib
beshak
Khubaib
myself Khalid Shabbir.Doctor of Anesthesia from PIMS Hospital.& belongs to Capital IslamAbad(Pakistan).
Khalid
yar sarfraz ap india se kab ay
Khubaib
tell me abt ethmoid bone
Sakshi
bro am all ready indian
SARFARAJ
okkk
SARFARAJ
hii sakshi how are you?
Khubaib
m gd..plz tell me the answer of it..
Sakshi
Face ki he ethmoid bone
Rakesh
ethmoid bone. Irregularly shaped bone anterior to the solenoid. Forms the roof of the nasal cavity, upper nasal septum, and part of the medial orbit walls.
LaKecia
Its unpaired bone of skull that saprate the nasal cavity from the brain it's located at the roof of the nose between the two orbits it's bone is one of the bones that make up the orbit of eye.
SARFARAJ
sphenoid I meant
LaKecia
wrist joint ka dusra name kya he
Rakesh
till me fast my ans
Rakesh
Also included in the ethmoid bone is the crista galli and the cribriform plates. The plates help form the roof of the nasal cavity and the floor of the anterior cranial fossa.
LaKecia
the outer most covering of the brain ( the dura mater) attached to the crista galli and helps secure the brain in the cranial cavity
LaKecia
Sakshi Mishra. I hope that helped!
LaKecia
thnks fo tellng😊
Sakshi
yup
Sakshi
yw
LaKecia
ye kya
Dr
hi
Dr
oh welcome sakshi
Khubaib
synovial joint will have present in wrist
sk
what's the smallest blood vessal in the body?
sk
respiration is the process of inspiration an expiration
Bel
first fall give me ans plz
sk
The protection of internal envirnment from the harm of external envirnmen is called as homeostasis.
Rana
Because stem cells have the unique ability to develop into any cell, stem cell therapy is being considered for treatment of kidney damage. What are your thoughts on stem cell treatment? Give at least three reasons for or against the treatment.
Samira Reply
to know the structure of the human body. to study the region of the human body. to understand the circulation of blood in the human body.
Angelashimakela Reply
what do CNS stand for
Angelashimakela Reply
central nervous system
Dustin
What does that mean
Shafiw
what does what mean
Larita
It means the system of brain and spinal cord! Sensory system of body!
rashid
is it where we find sensory gland?
Angelashimakela
glands are not a part of CNS! but sensory receptors are a part of peripheral nervous system!
rashid
PNS
rashid
👏
Angelashimakela
Ask what u want to?
rashid
structure, function and results
Dustin Reply
the pituitary gland lies in tha
Mohd Reply
tha pituitary lies in the
Mohd
the pituitary gland lies at the base of the brain between the hypothalamus and pineal gland.
nikki
which section of the pituitary gland has most secrations
Ehsanullah
What is the important role of FSH hormone?
Ehsanullah
pituitary gland lies in the sella tursica
Joseph
anterior pituitary has six important hormones
Joseph
The important role of FSH is that in females it stimulates growth and maturation of ova and in males it stimulates spermatogenesis..
Joseph
what is the important role of LH in females and males
Ayomide
the somatotrophs which secrete Somatotropin(Growth hormone) forms 50% of the secretory cells found in the anterior pituitary gland
Ayomide

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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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