Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Nutrition 3330 > 11 Vit D and Calcium > Flashcards

11 Vit D and Calcium Flashcards

1
Q

Vit D synthesized by?

A

skin

- needs sunlight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Forms of vitamin D?

A

D3 main form utilized by humans

- many forms exists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Active form of Vit D

-where is it converted

A

Calcitriol
1,25(OH)2 - D3

  • converted in the kidney

D3 –> calcidiol –> calcitriol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Synthesis of vit D

A

cholestrol –> 7-dehydrocholesterol –> Vit D

occurs in the SKIN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Food sources of vit D

A

fatty fish
fish liver oils
mushrooms
fortified dairy products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Absorption of Vit D?

A

incorporation into chylomicrons (because its fat soluble vitamin)
- transported in plasma bound to DBP (vitD binding protein)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Vit D

  • converted?
  • storage?
A

converted in KIDNEY

stored in LIVER and ADIPOSE TISSUE (other tissues)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Overall metabolic role of Vit D?

A

maintains calcium and phosphorus homeostasis

  • ensures availability in blood for bones/intestine
  • steroid hormone (vitamin D endocrine system)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How vitamin D acts as a steroid hormone?

A

Targets vit D receptors (VDR)

  1. 1,25(OH)2-D3 travels to specific cell
  2. enters cell, binds VDR
  3. binds DNA
  4. alters transcription rate or mRNA, synthesis of specific proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Main target organs of Vit D?

- others?

A

*bones and intestine

brain and nervous system
pancreas
muscle
cartilage
reproductive organs
cancer cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Vitamin D effect on other micronutrients

A

tight regulation of calcium

  • bone growth
  • maintenance of bone density
  • nervous system
  • blood clotting (vit K)

keeps phosphorus in normal range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What hormone vitamin D works with?

A

Parathyroid Hormone (PTH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What produces parathyroid hormone?

Where is it located?

A

Parathyroid Gland

- behind thyroid gland in neck

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Role of parathyroid hormone in kidney?

A
  1. stimulates activation of vit D
  2. increases calcium “reabsorption”
    - decrease urinary
    - increase blood
  3. decrease phosphate reabsorption
    - prevents hyperphosphatemia (prevents D’s conversion to active form)
    - calcium removed from bone also removes phosphate (keep P in check)
    - increase urinary phosphate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Role of parathyroid hormone in Bone

A

Increases osteoclast activity

  • bone resorption
  • release calcium and phosphorus
  • incr. blood calcium and phosphorus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hyper vs Hypo parathyroidism

A

Hyper

  • parathyroid gland tumor
  • lower bone density
  • high blood calcium (neg. feedback not working)

Hypo

  • removal or thryoid/parathyroid glands
  • low blood calcium (no sensor)
17
Q

1,25 (OH)2 - D3 acts on?

A

intestine

  • stims calcium and phosphorus absorption
  • Increase blood levels

bone

  • increase osteoclast activity
  • bone resorption
  • increase blood calcium and phosphorus
18
Q

PTH vs calcitriol?

A 
both calcium homeostasis (increase bl. levels)
PTH
- kidney and bone
Calcitriol
- intestine and bone
19
Q

Most abundant mineral in the body?

A

Calcium

20
Q

2 ways calcium is absorbed

A

Passive Absorption

  • D independent
  • concentration dependent

Active

  • D dependent
  • requires transporter and energy
  • requires calbindin (calcium binding protein)
21
Q

Calcium binding protein

- why needed?

A

Calbindin

  • free calcium very toxic
  • moves calcium across “intestinal” cell (shuttle)
22
Q

How does vit C help calcium absorption ?

A

Increases calbindin synthesis

- calcium binding protein

23
Q

Factors enhancing calcium absorption?

A 
vit D
calbindin synthesis
stomach acid
supplements (with meal)
optimal ratio calcium-phosphorus
24
Q

Factors inhibiting calcium absorption?

A 
low vit D
lack of stomach acid
excess phosphorus 
high fiber diet
phytic acid
oxalate (metabolite of vit C)
25
Q

Oxalate

A

inhibits calcium absorption

  • metabolite of Vit C
  • oxalate kidney stones
26
Q

Metabolic Roles of calcium

A

Major
- bone health

Minor

  • cellular processes
  • muscle contration - blood clotting
  • transmission of nerve impulses
  • membrane excitiability
  • second messenger
27
Q

Calmodulin

A
  • intracellular protein (calcium receptor) in all cells
  • binds calcium
  • activation of intracellular proteins and enzymes
  • mechanism of action of many peptide hormones
28
Q

Hormones involved in blood calcium homeostasis?

A

PTH
calcitriol
calcitonin

Nutrition 3330 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions