Chapter 5 - Dev And Aging Flashcards
(23 cards)
Discuss apositional growth & osgood-schlatter
Appositional growth = bone grows in length +girth by new tissue under periosteum
Osgood - schlatter = irritation of traction epiphysis of site where patellar tendon attaches to tibia below knee
- overuse threatens pain free ROM
What age do plates close, what relationship exists bw bone mineral density / mineral content
18-19
+ relationship bw postnatal growth in weight and bone mineral content/density
List 5 causes of bone loss w/ aging
1) H levels
2) dietary deficiencies
3) decr. Exercise
4) menopausal = decr. Estrogen BC of reg osteoblasts activity
5) prolonged calcium deficiency
Define osteoporosis, physical activity. Explain which extrinsic factors influences bone loss
Osteoporosis = less than average bone mineral density, eventually loss of bone strength as bones become porous through enlargement of canals and formation of spaces in bone greatly incr. risk of fractures
Physical activity = mech forces applied to bone to help maintain bone thickness and density
Extrinsic factors - h level, diet and exercise
Explain dev of muscle system in early dev with reference to
- sex diffs
- muscle fibre types
Fibres + cell grow during prenatal-life by trophy and plasia
@birth muscle mass is 23-30%
Plasia continue shortly after birth, the trophy
amount of incr. related to intensity muscle activity during growth = addition of sarcomeres @ muscle tendon junction allows muscle growth w/ skeleton
Boys - muscle mass incr. rapidly up to 17
Girls - until 13
Sex diffs related to hormonal influences
2 types of fibres
- slow twitch t1 for endurance
- fast twitch t2 a,x and b for short duration
Discuss muscle mass % in older adults, and list 4 possible causes for degeneration
After 50 = lose mass at faster rate. 30% lost by 80. Up to 50% can be lost
Causes
1) change in diet, lack of activity
2) heart ability to adapt to incr. workload
3) Bv lose elasticity
4) lifestyle And pathology
Explain the role of adipose, and discuss its dev in early life
Energy storage, insulation and protection
First appear in fetus at 3,5 months and incr. rapidly last 2 prenatal months. Rapid incr. first 6 months incr. Gradually until 8. Girls have dramatic incr. and adult women have higher fat%
Incr. by plasia + trophy but cell size not incr. dramatically until puberty. Childhood int. fat incr. faster than subcutaneous
Boys + girls subcutaneous incr. until 12/13 boys lose in mid adolescence
adipose persist once formed even w/ malnutrition
Discuss adipose in adulthood
- male body weight
- active vs sedentary
- redistribution
- social pressure
Male body decline after 50 BC of bone and muscle degeneration. Body fat continue incr.
Subcutaneous fat redistributes to abdomen = obesity = incr. risk of cvd
Active add less fat than sedentary
Overweight can be constraint
Social pressure and self esteem can discourage participation
Give function of endo system
Exert control over specific cellular functions through chem hormones. Secreted in hypothalamus and pit gland -> reg adrenal, thyroid amd sex glands
Give function of hormones
Stim protein anabolism = constructive anabolism = retention of substances needed to build tissue
List and describe the 3 hormones and their role in endo dev(and insulin)
GH
- influence growth in childhood and adolescence by stim proteins in anabolism = new tissue built
- Ant pit gland
- absence cause growth abnormalities
Thyroid hormones
- ant. Neck
- pit gland secrete TSH reg by TH by thyroid gland
- TSH release factor into hypothalamus
- endo Neuro connection
Gonadal
- affects growth and sex maturation
- androgens from cortex hasten fusion of epiphyseal growth plates
- promo skeletal maturation @ expense of linear height
- androgens role on muscle spurts by incr. nitrogen retention and protein synthesis
- estrogen promo - fat accumulation
Insulin
- prod in pancreas
- carb metabolism stim
- transport glucose and amino acids through membranes
- NB for GH functioning
- deficiency can decr.protein synthesis
Explain gradual imbalance theory
Overtime NS, endo and immune fail to function
Imbalance = incr. risk of disease
Women receiving hormone replacement @ menopause are incr. risk of cancers
Can be constraint to activity
Discuss prenatal growth of NS , and neuron maturation
Prenatal growth immature neurons differentiate and migrate to final position.
Proliferate at rate of 250k per min
200b form
3-4th month = all formed
Neuron cell body has 100k dendrites
Final position determined by 6th prenatal month
- brainstem= heartbeat and breathing
- CC = proprioception and thought
- cerebellum = posture
Migration NB to brain dev. Grows along chem trail and general destination and connects to others
Natural pruning process
List 2 potential causes of faulty neuron migration
Mom nicotine
Alcohol
An injury to the left cc can cause
Language deficits
Postnatal NS dev is susceptible to
Extrinsic factors
Define myelination
Process whereby axons of neural cells are insulated when myelin sheaths are formed by Schwann cells around axon
What stage marks an increase of myelination in postnatal dev
2-3 weeks after birth
Name and explain the 2 nerve pathways / tracts
Extrapyrimidal tract
- involved in deliver commands for random and postural movements made by infant
Pyramidal tract
- involved in myelination after birth
- 4-5months after controls finger movements
Define neurogenesis
Division and propagation of neurons
Explain the neural network theory
Signal travels through network. With age =’paths break at random meaning signals detour = slow reactions
What factors play role in NS changes
Extrinsic = rigorous exercise can minimize loss of neurons and synopses by constant supply blood
Define ossification centre. list and describe the 2 types
Site appears gradually in cartilage where bone is deposited
Primary
- mid portion of long bones
- form bone cells starting at fetal age of 2 months from centre outwards until birth when entire shafts are ossified
Secondary
- epiphyseal plates @ end of bone shaft
- plates has many cellular types where cartilage forms, grows, aligns and erodes to leave new bone in place
- bone laid downn@ epiphyseal plates to incr. bone length
- process of laying down new bones depends on adequate blood supply
- any injury that threatens blood supply threatens bone normal growth
- small bones ossify from centre outwards
