Unit 3 Flashcards
Function of bone
- Support
- Movement
- Protection
- Mineral storage
Osteon
Structural unit of bone–a central canal surrounded by concentric circles of bone cells
Osteocytes
Bone cells
Osteoblast
Bone forming cell, mature into osteocytes
Epiphyseal plate
Layer of cartilage separating the shaft and the end of a bone. Cartilage cells in the plate divide, lengthening and increasing the diameter of the bone. Also called the growth plate.
Describe the formation of bone in a fetus.
- A cartilaginous model of the bone is formed.
- Osteoblasts form bone around the shaft of the model.
- The shaft begins to hollow and spongy bone replaces the cartilage.
- Bone begins to form in the center of the ends of the bone.
- Cartilage remains only on the ends of the bone and in the growth plate.
The functional units of compact bone.
Osteons
How does bone grow in childhood?
Cartilage cells in the growth plates divide when signaled by sex hormones and the extra cartilage is replaced with bone.
Where in a bone is fat stored?
Yellow bone marrow
A condition characterized by a decrease in bone density that causes a weakened bone.
Osteoporosis
What holds two bones together at a joint?
Ligaments
Bone is hardened by which two minerals?
Calcium and phosphorus.
Cells that form bones
Osteoblasts
What hormones are involved in bone growth?
Growth hormone signals liver to release growth factor
Thyroid hormone modifies growth hormone activity to regulate proportion of bone growth.
Sex hormones signal division of cartilage cells in growth plates.
What hormones are involved in the cessation of bone growth at puberty?
Sex hormones (testosterone and estrogen)
Where is growth hormone produced? What are the consequences of too much/too little growth hormone?
Growth hormone is produced in the anterior pituitary gland. Too little GH results in dwarfism. Too much GH results in giantism.
Why are people today taller on average than in the 1700s (assuming same genetic background)?
Nutrition
What hormones are involved in regulating plasma calcium concentration? Why is this regulation critical?
Calcitonin and parathyroid hormone.
Because low levels of plasma calcium concentration can lead to osteoporosis.
What is the role of vitamin D in bone health?
Vitamin D ensures efficient absorption of calcium.
Why is daily exposure to sunlight a good thing?
Sunlight allows our bodies to produce vitamin D.
How many calories are in one gram of protein? carbohydrate? fat?
Protein = 4 calories Carbohydrate = 4 calories Fat = 9 calories
How many excess calories does a person have to eat to gain one pound?
3500 calories.
celiac disease
A condition in which ingestion of gluten causes an autoimmune response. Damaging to villi in the digestive tract, which impairs nutrient absorption.
cholera
Bacterial infection in the small intestine resulting in diarrhea.