Week 2 Pt 1 and Week 3 Pt 2 Flashcards
What are genes?
- basic unit of heredity
- 100s of genes chained within a chromosome
- a human cell contains 46 chromosomes
What is a genotype?
Blueprint of information in DNA
What is a phenotype?
observable traits
What was shown in the Polderman et al. 2015 - meta-analysis of twin studies?
- genes matter for motor skills: ~49% of variation in traits between twins are influenced by genetics
- physical function traits (e.g. skeletal, metabolic, muscular) have higher genetic influence than environmental traits
- influence of genes declines over time, in comparison to environmental influences (e.g. practice, training become more important for motor development)
What is the brainstem and what is its role?
consists of the medulla, pons and midbrain
- in charge of reflexes, breathing, maintaining posture, heartbeat, rhythm
What does the medulla do?
transmitter:
- sensory signals from spinal cord to thalamus
- motor signals from brain → spinal cord
respiration, blood pressure, HR
What does the pons do?
- coordination, posture
- involuntary influences
What does the midbrain do?
reflex movements from visual and auditory stimulation
What does the thalamus do? It is a part of the….
Important integration center
- part of diancephalon
What does the hypothalamus do?
- in charge of body temperature
- hormones
What is the frontal lobe of the brain in charge of?
- voluntary movement
- attention
- short term memory
- motivation
- planning
- speech
What is the parietal lobe of the brain in charge of?
- touch and body position
- reading and writing
What is the temporal lobe of the brain in charge of?
- processing sound
- forming memories
- language and meaning
What is the occipital lobe of the brain in charge of?
visual processing
What are the parts of the motor cortex we should know?
- primary motor cortex
- premotor cortex
- supplementary motor area
- posterior parietal cortex
What does the primary motor cortex do?
- actual execution of movements
- control speed and force of actions
What does the premotor cortex do?
- working memory
- plan and guide movement
What does the supplementary motor area do?
- preparation of movement
- voluntarily, internally generated
What does the posterior parietal cortex do?
- planned movements, spatial reasoning, attention
What does the basal ganglia do?
- integrate sensory motor centres
- unconscious behaviour
- planning and coordinating movements
- fundamental gross body movements
What does the cerebellum do?
- responsible for balance and the timing of movements
What do cranial nerves do?
transmit information within the brain
What do spinal nerves do?
transmit information within the spinal cord
What do schwann cells do?
- helps neurons in the PNS
- cells wrap around neurons within myelin sheaths
What is the all or none law?
- if a single motor unit receives a stimulus of sufficient intensity to bring forth a response, either all muscle fibres contract, or none at all
How does height changes from conception to infancy?
- rapid growth: 20x from 8 weeks to birth
- rapid growth in infancy - 50% taller than their birth length at 1 year old
How does height change with childhood growth?
- ~2 inches per year
- mid-growth spurt at age 7
How does height change in adolescence and puberty?
- ~3-4 inches per year
- girls start 2 years earlier than boys, finish by 16.5 years old
- boys grow until ~18 years old
How does height change in adulthood and beyond?
- height stays steady until 30s
- lose height as we age
What is bone mass?
combination of the size and density of your bones
What is the pre-natal timeline of skeletal growth?
- ~2 weeks: bone growth begins at onset of mesoderm cells
- ~6 weeks: bones appear in jaws/collarbone - then arms and legs
- 3rd month: ossification (cartilage into bone)
What happens during bone growth?
- bones grow longer and thicker
- long bones go through modeling resoprtion (extra bone tissue breaks down to maintain shape); middle stays slim, ends grow bigger
- short bones develop out of the core bone centre and enlarge
What is skeletal growth maturity? When does it happen?
- epiphyseal plate closure
- females: 13.5-18 years old
- males: 16-21 years old
- greater size in males post puberty
Females __% advanced skeletal maturity at birth
~20
What happens to body weight from conception to birth?
- 8 weeks: 14 g
- 5 months: 0.5 kg
- rapid growth in last 2 months
- birth: 3.2 kg
What happens to body weight in infancy?
- 3-4 months: 2x weight
- 1 year old: 3x weight
What happens to weight in childhood?
10 years old: 1/2 of adult weight
What happens to weight in adolescence?
- girls rapid weight gain 12-13 years old (16 kg)
- boys rapid weight gain (13-15 years old (20 kg)
What happens to body weight in adulthood?
- 20x weight than at birth
- declines later in life due to bone and muscle tissue loss
In those with anorexia nervosa, bone density is how much lower than healthy peers?
25%
What percentage of body fat is influenced by genetics?
25-70%
What is the growth of body fat over time?
- 7-8th prenatal month: start of body fat growth
- birth: body fat 16%
- 1 year old: body fat 24-30%
- 5.5-7 years old: mini growth spurt
What is the sex difference regarding body fat?
- boys slow down
- girls continue to gain through puberty
What is hyperplasia?
increase in cell number; rapid growth before birth and into first year of life
What is hypertrophy?
increase in cell size; dependent on food intake, can lead to hypertrophy in tandem
What is the growth patterns of muscle tissues by type?
- birth to childhood: type 1 is 50%, type II is 25%
- adulthood: 50-50 ratio
What is the growth patterns of muscle tissue by size?
- 1 year old: 30% of adult size
- 5 year old: 50% of adult size
- adult size: 50-60 micrometers
Describe physical growth in advanced aging
- heigh decreased with age
- weight increased steadily from 20s to 55-60 years old and declines after
- lean body mass decreases with age due to bone and muscle mass decline
Describe fat storage in males and females
- males store fat in belly
- females store fat in the hips, thighs, breasts
What are the 4 “ages” to know?
morphological, dental, sexual, and skeletal
What is sexual age?
- primary characteristics (reproductive organs)
- secondary sex characteristics (pubic hair, breast development)
Sexual age in females can be indicated by…
- menstruation
- menstruation ≠ ready for reproduction
What is the sex differences seen with skeletal age?
- girls: ~20% ahead of boys in skeletal maturity
- hit milestones earlier than boys
What are maturity variations?
- early, average, or late maturation
- measured by comparing skeletal age to chronological age (20% difference from average, or 1-3 years, classifies an early/late maturer)
- differences between early/late shows up often in adolescence
- late maturers “catch up” to early maturers in late adolescence
What are secular trends?
- we grow and mature earlier and faster than previous generations
- better health, nutrition, and living conditions
- not all positive: we carry more body fat today, physical activity has dropped
Why is balanced nutrition important in development?
- diet is a potent environmental influence
- for maintenance and repair of body tissues
How does under nutrition play a role in development?
- lack of energy due to low calories of quality protein
- stunted growth risk
The risk of obesity is related to heredity by what percentage?
25-70%
How does breastfeeding play a role in postnatal development?
- breast milk antibodies → help babies resist infections
- reduced risk for overweight, delays in motor development
Physical activity has little to no effect on stature, body proportion, physique, skeletal maturity or sexual maturation. However, it is linked to…
- regulate/maintain body weight
- enhance bone mass, bone development
- increase muscular development in adults and post-pubertal children; lesser in older adults
- increase physiological regulation
- increase motor skill development
