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Calcium and phosphate are used for much more than
bone structure
Phosphate is a component of DNA, RNA, ATP,
phospholipids, and pH buffers
Calcium needed in neuron communication, muscle
contraction, blood clotting, and exocytosis
Minerals are deposited in the skeleton and withdrawn
when they are needed for other purposes
Hypocalcemia: low blood sugar has a wide variety of causes, blood
calcium excess
:Vitamin D deficiency
:Diarrhea
:Thyroid tumors
:Underactive parathyroids
:Pregnancy and lactation
:Accidental removal of parathyroid glands during thyroid
surgery
Calcium homeostasis depends on a balance between
dietary intake, urinary and fecal losses, and exchanges
between osseous tissue
Calcium homeostasis is regulated by three hormones:
:Calcitriol, calcitonin, and parathyroid hormone • Joint (articular) capsule—connective tissue that encloses the cavity and retains the fluid
- Outer fibrous capsule: continuous with periosteum of adjoining bones
- Inner, cellular, synovial membrane: composed mainly of fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity
• In a few synovial joints, fibrocartilage grows inward from the joint capsule
- Articular disc forms a pad between articulating bones that crosses the entire joint capsule
• Temporomandibular joint, distal radioulnar joints, sternoclavicular and acromioclavicular joints
- Meniscus: in the knee, two cartilages extend inward from the left and right but do not entirely cross the joint
• These cartilages absorb shock and pressure
• Guide bones across each other
• Improve the fit between bones
• Stabilize the joints, reducing the chance of dislocation
• Accessory structures associated with synovial joints
- Tendon: a strip or sheet of tough collagenous connective tissue that attaches muscle to bone
• Most important structures in stabilizing a joint
- Ligament: similar tissue that attaches one bone to
another
**- Bursa: a fibrous sac filled with synovial fluid, located between adjacent muscles, where tendon passes over bone, or between bone and skin
• Cushions muscles, helps tendons slide more easily over joints, modifies direction of tendon pull
- Tendon sheaths: elongated cylindrical bursae wrapped around a tendon
• In hand and foot • Slow oxidative (SO), slow-twitch, red, or type I fibers
- Abundant mitochondria, myoglobin, capillaries: deep red color
• Adapted for aerobic respiration and fatigue resistance
- Relative long twitch lasting about 100 ms
- Soleus of calf and postural muscles of the back
• Fast glycolytic (FG), fast-twitch, white, or type II fibers
- Fibers are well adapted for quick responses, but not for fatigue
resistance
- Rich in enzymes of phosphagen and glycogen-lactic acid
systems generate lactic acid, causing fatigue
- Poor in mitochondria, myoglobin, and blood capillaries which
gives pale appearance
• SR releases and reabsorbs Ca2+ quickly so contractions are
quicker (7.5 ms/twitch)
- Extrinsic eye muscles, gastrocnemius, and biceps brachii
• Ratio of different fiber types
have genetic predisposition— born sprinter
- Muscles differ in fiber
types: gastrocnemius is predominantly FG for quick movements (jumping)
- Soleus is predominantly SO used for endurance (jogging) The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain. As the "master gland" of the body, it produces many hormones that travel throughout the body, directing certain processes or stimulating (causing) other glands to produce other hormones.
Prolactin - Prolactin stimulates breast milk production after childbirth. It also affects sex hormone levels from ovaries in women and from testes (testicles) in men, as well as fertility.
Growth hormone (GH) - GH stimulates growth in childhood and is important for maintaining a healthy body composition and well-being in adults. In adults, GH is important for maintaining muscle mass and bone mass. It also affects fat distribution in the body. Read about growth hormone excess.
Adrenocorticotropin (ACTH) - ACTH stimulates the production of cortisol by the adrenal glands—small glands that sit on top of the kidneys. Cortisol, a "stress hormone," is vital to our survival. It helps maintain blood pressure and blood glucose (sugar) levels, and is produced in larger amounts when we're under stress—especially after illness or injury. Read about having too much ACTH.
Thyroid-stimulating hormone (TSH) - TSH stimulates the thyroid gland to produce thyroid hormones, which regulate the body's metabolism, energy balance, growth, and nervous system activity. Read about TSH-secreting tumors.
Luteinizing hormone (LH) - LH stimulates testosterone production in men and egg release (ovulation) in women.
Follicle-stimulating hormone (FSH) - FSH promotes sperm production in men and stimulates the ovaries to produce estrogen and develop eggs in women. LH and FSH work together to enable normal function of the ovaries and testes. it effects Sternoclide mastoid
Whiplash is a neck injury that can occur during rear-end automobile collisions, when your head suddenly moves backward and then forward — similar to the motion of someone cracking a whip. These extreme motions push your neck muscles and ligaments beyond their normal range of motion.
Whiplash injuries can be mild or severe. Treatment typically begins with over-the-counter pain relievers and ice applied to the painful neck muscles. If pain persists, prescription medications and physical therapy may be helpful.
Most people recover from whiplash in just a few weeks, but some people may develop chronic pain after a whiplash injury.
In a whiplash injury, it is possible to injure the joints, discs, vertebrae (bones), ligaments, nerve roots, and even the spinal cord. However, in 80% of patients, the source of pain can be isolated to one of three main structures: 