KIN 320 - Post Midterm 1

Two adult mice are born from the same litter but one is significantly larger than the other. Why?

the smaller one is not releasing growth hormones

growth results from an interaction of what 4 factors?

1. genes
2. hormones
3. nutrients
4. environment

Say whether each factor is environmental, genetic, or interaction: Language, eye color, weight, skin color, religion, blood type

genes establish the ______,__ environment determines if the potential is _____________

* potential
* obtained

What is inherited is ___ everything else is ______

* DNA
* developed

What is monozygotic? Dizygotic?

Monozygotic - embryo split, identical twins

Dizygotic - two embryos, fraternal twins

Who has a greater difference in height, mono or dizygotic?

Height difference greater between DZ than MZ

Label

Commander and 2nd in command of endocrine system

* hypothalamus
* pituitary gland

What does pituitary release?

* human growth hormones
* trophic hormones that control other glands

Why was Charles Byrne so tall?

* pituitary tumor
* pituitary tumors associated with acromegly - head, hands, feet begin to grown long after normal growth stops

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Growth hormones is produced by?

It is secreted in a _______ pattern in response to?

* produced by anterior pituitary
* pulsative pattern
* in response to growth hormone releasing hormone (GHRH) and somatostatin

2 effects of growth hormone

anabolic

* stimulation of bone development

Metabolic

* insulin resistant actions

Insulin like growth factor (IGF) function?

* major mediator of growth of skeletal and lean tissue in children

Factors affecting GH and IGF-1

* acute physical activity
* sex hormones during puberty
* nutrition
* genetic

GH/IGF-I Axis

* anterior pituitary releases GH pulsatile bursts every 2 hours
* GH may stimulate IGF-1 release from the liver
* GH and IGF-1 may both contribute to peripheral tissue growth

how is GH release stimulated?

by exercise

True or False - repeated bouts of exercise will increase GH concentrations and therefore result in increased final stature

False - repeated bouts do not result in increased finals stature

2 other growth determinants

* insulin
* thyroid hormone

How does insulin effect growth?

* synergistic effect with growth hormone to increase protein synthesis in the muscle
* IGF -I activity on linear bone growth is facilitated by insulin

How does thyroid hormone effect growth

* stimulate oxygen uptake and energy expenditure in most tissues
* essential for GH to exert is full affect
* promotes IGF-1

hypothyroidism

* short stature
* lower growth
* delayed bone growth
* cretinism - hypothyroid face - iodine deficiencies during infancy

blood levels of growth hormones during growth

* sharp increase in GH during adolescence
* a consequence of the rise in sex hormones

IGF-1 during growth

* sharp increase during adolescence

estradiol

* most active of estrogen hormones
* acts to develop sexual function
* stimulated by pulsatile release of FSH follicle stimulating hormones and LH luteinizing hormone

FSH and LH stimulate the ovary to produce

progesterone

what happens to produce ovarian hormones

pulsative secretion of GnRH into the anterior pituitary leads to release of FSH and LH which produces ovarian hormones

What are the phases of the menstrual cycle. Include and start at menstruation

Follicular phase:

* day 0-14
* day 0-4 menstruation

Luteal phase:

* day 14-28

Describe hormone levels in the follicular and luteal phase of the menstrual cycle

Follicular Phase:

* increase in Estradiol, FSH, LH
* FSH and LH peak right before ovulation with LH peaking the highest

Ovulation

Luteal Phase:

* decrease in estradiol, FSH, LH
* increase in progesterone
* if egg is fertilized progesterone will continue to increase

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Label

1. menstruation
2. estradiol
3. ovulation
4. progesterone
5. FSH
6. LH
7. follicular phase
8. luteal phase

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What is the sex hormone in males. Where does it act? what does it release?

* gonadotropic releasing hormone GnRH
* acts on anterior pituitary to release FSH and LH
* LH acts on Leydig cells → testosterone
* FSH stimulates the Sertoli cells → sperm

leptin is an appetite ______

suppressant

serum leptin levels is related _______ to body fat

exponentially,

* increased fat= increased leptin, your body makes more to try and suppress
* leptin is produces in adipocytes of subcutaneous fat tissue

absence of leptin prevents _______

sex maturation

* so increasing leptin is going to increase maturity

Leptins relationship with nutrition status and reproduction

Critical Body Fat hypothesis:

* Frish and Revelle (1970) suggested that a body mass of 48 kg and fat of 22% was needed to trigger a change in metabolic rate that leads to menarche

agree with critical body fat hypothesis?

may agree with frisch and revelles argument but menarche still initiated below Frisch and Revelle critical values

Stages of amenorrhea

* primary: delayed, absence by 16 yrs
* secondary: absence of 3+ consecutive cycles, most common
* oligomenorrhea: periods longer than 35 days
* luteal deficiency: length of menstruation is normal but progesterone levels low (fertility issues)

What sports is ammenorhea higher? lower?

* higher in endurance sports - intensity training correlated with frequency
* lower in swimming - no correlation with intensity

two theories of causal mechanisms of Amenorrhea

* exercise stress model
* energy availability model

Exercise stress model

Exercise stress increases stress hormones (cortisol) which provide negative feedback to hypothalamus which decreases sex hormones (LH, FSH, estrogen)

energy availability model

* increased training + increased caloric demand = nutritional inadequacy and negative caloric balance
* shuts of GnRH pulse generator
* decreases LH, FSH, Estrogren,

A study on the mechanism of Amenorrhea found that Luteal hormone pulsativity is disturbed by _____ rather than _____

* energy unavailability
* exercise

physical activity

* any bodily movement produced by skeletal muscles and results in energy expenditure
* has a mechanical ROM, physiological and behavioural (motivation) components

exercise

* physical activity that is planned, structured, repetitive, and results in improvement or maintenance of one or more facets of physical fitness

physical fitness

* a set of attributes (cardio-respiratory endurance, power, etc.) that people have or achieve that relate to their ability to perform PA

physical activity characterized in dimensions and contexts. Describe dimensions

* energy expenditure
* FITT formula (frequency, intensity, time, type)

physical activity characterized in dimensions and contexts. Describe contexts

**contexts (PA)**

* **leisure-time**
* **occupational**

energy expenditure

**energy expenditure**

* **TEE = REE + DEE + EEE + adaptive EE**
* **total energy expenditure**
* **Resting energy expenditure (basal)**
* **diet-induced energy expenditure - thermogenesis (digestive process)**
* **exercise induced energy expenditure**

resting energy expenditure

* measured in the morning in a rested and fasted state
* supine position
* room temp (23-25F)
* 20-30 min

exercise-induced energy expenditure

* expended during PA
* most varied
* range from 0 in sedentary to 10-20x REE during intense exercise

diet-induced energy expenditure

* increase from REE observed 3-4hrs after a meal
* EE for digestion and absorption

metabolic equivalent (MET)

* ratio of exercise to resting energy expenditure
* EEE / REE
* most commonly used
* based on adult values
* EEE per unit body mass during activities is higher in children than adults
* resting metabolic rate of children per unit body mass or surface area is higher in children

subjective instruments

* recall questionnaire
* recall interview
* proxy-report
* activity diary
* observation

self-report

* self-assessed recall
* proxy reports
* diaries, interviews
* questionnaires
* most widely used
* ease and low cost
* interviewer administered questionnaires have high reliability and validity than self-administered
* however higher cost in terms of observation time
* diaries tend to result in large degree of behaviour change

self-report (concerns)

* not directly assessing PA
* reliance on cognitive ability to recall specific events (memory)
* bias
* grading

observation

* long standing method - video and computer technology allowed complex observational codes
* reliable and observers easily trained
* labor intensive, time, consuming and costly
* mostly done in structured situations (activity classes, sports, etc.)

objective instruments

* pedometers
* electronic motion sensors
* accelerometers (most common)
* heart rate monitoring
* indirect calorimetry (VO2 max, metabolic carts)
* doubly labelled water (gold standard)

heart rate monitors

* most popular method for estimating EE over long periods
* assumes two regressions lines for determining EE
* at rest - relatively linear
* during exercise
* commonly used in children (good adherence, minimal restrictions)
* other factors influence HR

pedometers

* objectively documents mechanical aspect of activity
* counts and registers the number of movements (when attached at waist measures strides)
* not sensitive to intensity only number (can't distinguish between walk and run)

accelerometers

* electronic motion detectors
* measure frequency and intensity in vertical plane
* uniaxial
* triaxial (more recent)
* GPS functions (some newer models)
* custom software is used to reduce the raw data into minutes of moderate to vigorous PA per day using intensity cut points and Epochs

epoch

* user defined interval of time
* counts every second how many steps you take
* average the steps over that specific amount of time
* want this to be very small with children

cut points

* different types depending on intensity
* data will be analyzed differently
* differs in the activities that are used to create a range of counts/min for different analysis

accelerometers (concerns)

* adherence (7 days during waking hours ideally)
* practicality (can't get wet, not worn during aggressive contact sports)
* application for different context
* cost ($200 US per device)
* cut point consistency (how accurate it is)
* concerns about whether it assess FITT (epochs in children)

physiological analyzes

* typically used to assess EE
* assumes 1L O2 consumption = 5kcal
* metabolic cart
* canopy method
* respiration chamber
* doubly labeled water

metabolic cart

* most commonly used is computerized metabolic cart
* minute ventilation
* individual must remain close to metbolic cart

portable device

* allow direct measure of VO2 while individual is freely moving
* still limited use in children

validity in children

* more diverse range of activities than adults (less structure, more spontaneous)
* less memorable activities (children have poor recall)
* cognitive abilities
* short duration activities

patterns of PA participation. 3-10yrs. Intensity? Older children? organization?

* 3-10 years PA is often spontaneous and non-organized and is of intermittent bouts
* high intensity bouts did not last more than 3 seconds and 95% of lasted less than 15 seconds
* PA patterns of older children and adolescents tend to be more organized and of a more regular, prolonged nature
* in adolescence most PA occurs after school

Does level of PA or EE or both decline with age?

both

females (young girls)

What sex does PA decline start earlier and more rapidly?

True or False: PA tracks well

false (does not)

Does it appear as if participation in PA is differeing between low and high risk males or females

No it does not appear

When PA is organized by age category, who has increased PA, males or females? When organized by maturity or years from peak height velocity?

Age category

* males increased PA
* females decreased PA

Years from PHV

* no difference between the sexes in PA levels

T/F there was an engagement difference in PA when organized by chronological versus biological age

true

Does PA affect stature?

NO

* PA not associated with attained height
* PA has no negative effects on stature

Studies done to prove PA has no effect on stature

* short gymnasts also had short parents
* studies suggested PA increased height, but maturation level was not considered. Maturation is a confounding factor for PA

Does PA affect physique?

* distribution of somatotypes does not appear to be different between active and inactive
* PA individuals have greater MESO, sport specific somatotypes

PA effects on body weight

* weight differences minimal between active and inactive
* more differences in the composition of weight (bone mass, fat free, lean)

training regularly may have the ______ impacts on body composition

largest

PA effects on bone

increased PA = increased bone mineral content and bone geometry

PA and fat free mass

* increased Lean tissue mass: PA beneficial to LTM and muscle mass during adolescence and adulthood
* increased hypertrophy: may be task dependent (weight train yes, endurance inconclusive)
* Fiber type: no evidence to suggest fiber type can change with PA, only fiber size

PA and fat mass

* reduce fat mass developed (minimal differences subcutaneous at extremities, greatest difference at trunk)
* reduce FM gained during adolescence, especially females

PA effects on skeletal maturity

does not influence skeletal maturity

PA and somatic maturity (measured by age of peak height velocity)

PA does not influence age of PHV,

may influence PA involvement

PA and sexual maturity

* ? inconclusive
* some evidence that age of menarche differs between PA groupings, may be confound by other factors
* no evidence to suggest tanner stages differs between PA groups in males

In general, does regular PA effect stature

no

In general, does regular PA effect somatotypes

yes

In general, does regular PA effect body weight (body composition)

no to body weight, but yest to body composition

In general, does regular PA effect bone tissue

yes

In general, does regular PA effect skeletal muscle

yes

In general, does regular PA effect adipose tissue

yes (mostly in females)

In general, does regular PA effect sexual maturity

?

ectoderm

* outer layer
* outermost tissue (skin)
* brain and nervous systems

mesoderm

* middle layer
* skeleton and bone marrow
* muscle, hear and blood

endodern

* inner layer
* linings of internal organs

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Fetal circulation has 3 shunts

1. foramen ovale (connects 2 atria allowing bypass of right ventricle and lungs)
2. ductus arteriosus (connects arteries between lungs and aorta, bypasses lungs)
3. ductus venosus (bypasses liver)

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What happens to the shunts

at birth, rapid closing of the shunts to establish post-natal circulation

main reason why shunts close

pressure (taking first breath and blood flows creating pressure)

what would happen if the foramen ovale or the ductus arteriosus did not close?

blood pools in atria

what would happen if the ductus venosus did not close

blood would not go to liver