Midterm 3 Flashcards
How many pairs of chromosomes does each human have?
23 = 46 chromosomes total
- 22 pairs of chromosomes (autosomes) and 1 pair of sex chromosomes
- Each pair contains 2 chromosomes, 1 from each parent
What are gametes?
Ovum (eggs) and sperm
- Contain 23 chromosomes
- When egg and sperm fertilize, it contains 23 pairs
What parent determines sex?
Father
- Females are XX, male is XY
What are disorders of sexual development?
Intersex
- chromosomal sex is inconsistent with phenotypic sex (reproductive organs)
- Some individuals have both female and male anatomy
What is prenatal development controlled by?
Genes
- Leads to normal development or abnormal development
- Sensitive to nutrients, viruses, drugs, physical activity
What is embryonic development?
Conception to 8 weeks
- Differentiation of cells to form specific tissues and organs
- Limbs formed and heartbeat begins at 4 weeks
- Human form noticeable at 8 weeks
- Eyes, ears, nose, mouth, fingers and toes are formed
- Size of a bean
What is fetal development?
8 weeks to birth
- Growth by hyperplasia (increase in cell number) and hypertrophy (cell size)
- Cephalocaudal (head to toe) - head and facial features grow fastest, followed by upper body and slower growing lower body
- Proximodistal (near to far) - trunk advances first, then nearest part of limbs, then distal parts of limb
What is fetal nourishment?
Oxygen and nutrients diffuse between fetal and maternal blood in placenta
- Poor maternal health status can affects fetus
What is genetic abnormal prenatal development?
Trisomy 21 - Down syndrome
What is structural abnormal prenatal development?
Congenital heart defects
- Often no clear cause
- Genetic, exposures, diet, maternal disease
What are congenital abnormalities?
Wide range of abnormalities of body structure or function that are present at birth and are of prenatal origin
- Can be genetic or external
What is an external exposure abnormal prenatal development?
Teratogen - agent or factor that causes abnormal prenatal development upon exposure
ex. Rubella virus - harmful if exposed during first 4 weeks. Earlier exposure = more serious abnormalities
What are external causes of abnormal development?
Pressure, temperature, Xrays, pollutants
What is physical growth?
quantitative increase in size
What is development?
Continuous process of change in functional capacity
- ability to live, move and excel in the world
- Humans are always developing but change may be more or less noticeable at certain points
What is Maturation?
developmental process leading to a state of full function
- An adult like state
- Maturation implies progress toward physical maturity, state of optimal functional integration of individual’s body systems and ability to reproduce
What figure does growth follow?
Sigmoid (S)
- Rapid growth after birth, followed by gradual but steady growth during childhood, then rapid growth during early adolescence
When is peak height velocity? When does growth stop?
Girls
- Peak height velocity - 11.5-12 years
- Tapers off around 14, ends around 18
Boys
- Peak height velocity - 13.5-14 years
- Tapers off around 17, ends around 18
What pattern does weight follow?
Sigmoid
What is weight susceptible to?
Diet and exercise
When is peak weight velocity?
Boys - 2.5-5 months
Girls - 3.5-10.5 months
What is menarche?
First menstruation
Why is the age of menarche decreasing?
Diet, sedentary behaviour, low physical activity
- Physical activity reduces estrogen
What are factors associated with early menarche?
Risky sexual behaviour, Obesity, Diabetes, Cardiovascular disease, Breast cancer
What is the Tanner and Marshall scale?
Male development
What are sex differences in brain development?
Prefrontal cortex matures 2 years later
- Impulse control, planning, self-regulation, decision-making, judgment
Cerebellum reaches full size for girls at 11 and 15 for boys
- Modulates emotional, cognitive and regulation capacity
What are the sex differences in play?
Boys - Weapons and competition, play fighting
Girls - Domestic toys and play
What are the sex differences in aggression in play?
Girls - relational aggression - intentional harm caused to others by damaging social relationships or feelings of peer acceptance
Boys - physical aggression
What are the physiological assessments of maturation?
Ossification (hardening) of bones
Why can height decrease older adulthood?
Compression of cartilage pads
Osteoporosis - bone density loss
When does ossification begin?
6th or 7th week
How many neutrons are created every minute? (prenatal)
250,000
What do compact and spongy bone develop from?
Sheets of connective tissue
Where does growth in bone length occur?
Secondary ossification centres - epiphyseal plates
When does muscle mass stop increases?
Girls - age 13
Boys - 17 years
What percentage of body weight does muscle account for?
Women - 45%
Men - 54%
What is adipose tissue used for?
Energy storage, Insulation, Protection
When does fat increase until?
Rapidly until 6 months
- Gradually until 8 years
Children have more ____ fat while adults have more _____
visceral, subcutaneous
What is growth hormone?
Secreted by anterior pituitary gland
- Necessary for normal growth
- Deficiency can result in growth abnormality
What do thyroid hormones influence?
Whole body growth
What are gonadal hormones?
Influence on growth, sexual maturation
What percentage of the adult weight is the brain at birth and at 4 years?
Birth - 25%
4 years - 80%
What does the first 1000 days influence?
Everything!
- poor nutrition can cause irreversible damage to a child’s growing brain
- child that is read to, talked to, sung to, etc has better cognitive capacity, lives fuller more productive life
What does osteoporosis cause?
rib cage collapse, stooped posture, reduced height
What percentage of muscle is lost by age 80
30%
What is the average weight gain from adipose tissue?
1.1-2.2lbs/year
women - 22lbs
men - 19lbs
What is strength?
ability to exert force
What age are boys and girls similar strengths until?
13
Is strength training good for children?
Yes
At what age does strength start to decrease?
After 30s
- Associated with muscle atrophy and loss
- Called sarcopenia
- Caused by malnutrition, age, lack of physical activity, genetics
How do adolescent boys and girls differ with growth?
Boys - experience large spurt of growth in strength
Girls - continue with steady increase
What is flexibility?
Ability to move joints through full range of motion
Why are infants and toddlers more flexible?
Babies have more flexible cartilage
- As child grows some cartilage hardens and turns to bone, some bones fuse together
- Kids are also more active
Why are girls more flexible than boys?
Flexibility exercises are socially acceptable for girls
- Girls participate in activities stressing flexibility (yoga, dance)
When do adults really start to lose flexibility and why?
Age 50
Little used joints
What is PNF stretching?
Proprioceptive neuromuscular facilitation
- most effective for increasing ROM
What are the types of stretching?
static, passive, PNF, dynamic
Does stretching improve performance?
It can actually decrease
- Temporary strength deficit (reduces explosive force)
- sprintin/jumping
- static stretching
Does stretching reduce injuries?
High flexibility can increase injury risk
What is the trend with children and cardiorespiratory health?
Trending towards reduced fitness
- High percentage of children have risk factors for heart disease
- Cardio endurance reflects ability to sustain vigorous activity
What is aerobic exercise?
exercising at an intensity which you are able to take in enough or more oxygen than you need
- continuous movement fuelled by oxygen from the air you breathe
- body uses oxygen to make ATP
Why can some people sustain more aerobic exercise than others?
Cardiac output
- how much blood your heart can pump out in 1 minute
- supplies muscles, tissues and brain O2
- average healthy person is 5L/min at rest
How to increase cardiac output?
Increase stroke volume or heart rate
- Training
What is anaerobic exercise?
Oxygen reserves and energy stores are used without oxygen
- Brief intense activity
- Not more than 2-3 mins
- Produces ATP by breaking down glucose (glycolysis)
What changes as children age in anaerobic performance?
Energy reserves increase (muscle mass)
Tolerance of lactic acid
Anerobic power improves
Why do children have a smaller output of anaerobic power?
Less muscle mass
Energy reserves are smaller
What changes in aerobic performance as children age?
Children have smaller stroke volume and smaller cardiac output
- Compensate with higher heart rate
- Lower concentrations of hemoglobin
What happens as children age? (aerobic)
Heart size increases
Hemoglobin concentration occurs
- ability to sustain exercise is related to body size and maturity
What affects anaerobic performance in older adulthood?
Loss of muscle mass and type 2 fibres
How much does maximal oxygen uptake per kg of body weight fall after 20s?
1%
What changes occur in structure and function in adulthood
Loss of cardiac muscle, loss of elasticity in cardiac muscle, Thickening of left ventricle, Fibrotic changes in valves, Loss of elasticity in major blood vessels
What is human movement based on?
Information about the environment and one’s position or location in it
What is the difference between sensation and perception?
Sensation - sensory receptors detect sensory stimuli
Perception - organization, interpretation, and conscious experience of sensations
What are the sensory systems?
Visual, kinesthetics, auditory
What is acuity?
Sharpness of sight
What is acuity in first month of life, at age 5 and age 10?
First month - 20/400
5 - 20/30
10 - 20/20
What is presbyopia? And what causes it?
Affects ability to see nearby images
- Becomes clinically significant ~40
- older adults need more light in dim environments
Caused by less flexible lens
What does visual perception involve?
Perception of :
- space
-movement
-objects
What is the perception of space?
Requires perception of depth and distance
- Often derived from eyes being in different locations or movement of head
At what age can children perceive depth?
6 months
- May err in judging depth until near-adult levels are reached
- Number of older adults who fail depth perception tests is higher than young adults
What is the kinesthetics system
Gives us body sense (where we are in space)
- vital to ability to position ourselves, move in environment, identify objects we contact
Kinethesis provides sense of force, heaviness and effort
Where does kinesthesis come from?
Proprioceptors
What are the types of proprioceptors?
Somatosensors - located under skin, in muscles, at muscle-tendon junctions, in joint capsules and ligaments
- make us feel touch, pain, temp.
Vestibular apparatus
- houses receptors located in inner ear
- allows I=us to detect position and movement of heead in space
- enable hand-eye coordination, posture, equilibrium
What is tactile localization?
Ability to identify without sight the exact spot on the body that has been touched
When does manipulation become methodical?
~6 years
What is the difference between pure dominance and mixed dominance?
Pure - favoured side is same for all body parts
Mixed - not the same
What are kinesthetics changes with aging?
Some sensitivity may be lost
Proprioceptive acuity declines
Impairments in lower limbs may play role in loss of balance
