Lecture Nine Flashcards
What is adolescence and adulthood characterised by?
Adolescence -Characterised by: o Body systems reaching maturity (structurally and functionally) -Sexual maturity o The timing and tempo of changes is highly variable between individuals and gender Adulthood -Characterised by: o Attainment of full maturity o Peak performance and development
Describe the portion changes
- Head x 2
- Arms x 4
- Trunk x 3
- Legs x 5
What are the sitting height/stature ratio in relation to leg and trunk length?
-Relative leg length and trunk length
o Infants have smaller legs
o Lower extremities grow faster than trunk during childhood and adolescence = ratio declines
o Late adolescence the ratio increases again when trunk grows after leg growth has ceased
o Females have generally shorter lower extremities than males
What are the sitting height/stature ratio in relation to shoulder to hip ratio?
-Biiliocristal Breadth to Biacromial Breadth ratio
-Breadth of hips compared to shoulders
o Ratio higher in females indicating
-Females hips make up a greater % of their shoulders
-Males ratio declines as shoulder increase in size faster and greater than their hips
What accounts for the difference in adult stature?
-Primarily by boys experiencing 2 years more of preadolescent growth than girls
o Boys gain at ~5cm/year during females’ growth spurt = 10 cm of growth females don’t experience
o Males have a higher peak
o Testosterone increases Ca2+ deposition = bone growth
-Mid growth spurt during childhood (6.5-8.5 years)
o Not always apparent, more common in males.
-Attainment of adult stature:
o Growth can continue into mid 20’s
o Annual increment of less than 1.0 cm
o Four successive months increments of less than 0.5 cm
What is the bone matrix and bone cells that make up bones?
o Bone Matrix -35% organic -Collagen and Proteoglycans -Flexible strength -65% inorganic -Minerals = calcium and phosphate -Weight-bearing strength o Bone Cells -Osteoblasts -Bone forming cells -Produce organic material -Osteocytes -Osteoblasts surrounded by bone matrix -Osteoclasts -Bone-destroying cells -Reabsorption or break-down
What are the four zones of the growth in bone length?
o Zone of Resting
-Chondrocytes do not divide
o Zone of Proliferation
o -Chondrocytes produce new cartilage
o Zone of Hypertrophy
-Chondrocytes produced in the Zone of Proliferation enlarge and mature
o Zone of Calcification
-Hypertrophied chondrocytes die, blood vessels from the diaphysis grow, osteoblasts deposit new bone matrix
-Reach adult size when the Epiphyseal plate ossifies and becomes a line
What is the growth in articular cartilage?
- Articular cartilage at the end of the bone grows similarly to inside the bone
- No clear-cut zones
- Outer cartilage similar to zone of resting
- Inner cartilage calcifies and ossifies
- When it reaches full size bone stops replacing cartilage
- This cartilage doesn’t become ossified unlike the epiphyseal plate
What is the growth in bone width?
- Bone is deposited by osteoblasts on the outer surface
- Bone is reabsorbed by osteoclasts on the inner surface
What are the somatotypes?
-Somatotyping is a system of classifying body types in terms of three categories: o Endomorphic (relative fatness) o Mesomorphic (relative musculoskeletal robustness) and o Ectomorphic (relative linearity or slenderness of a physique).
What is somatotyping classified on?
- The three numbers together give a somatotype number, with the Endomorphic score first, then Mesomorphic and finally Ectomorphic
- The scores may also be plotted in a shield diagram or somatograph, representing the somatotype on a two-dimensional scale.
What would someone with a ectomorph somatotype look like, what are the calculations for the ectomorph rating based off and what are the typical sports they play?
-An ectomorphic person would be: o Tall and thin o Narrow body o Thin arms and legs o Little body fat o Wiry muscles o In general, ectomorphs rank high on endurance, flexibility and agility -The calculation for the ectomorph rating is based on the measurements of: o Height o Weight o Height/weight ratio -Typical sports o Basketball o Long distance runners -Both examples have high ectomorph ratings but also relatively high mesomorphic ratings
What would someone with a mesomorph somatotype look like, what are the calculations for the ectomorph rating based off and what are the typical sports they play?
-A mesomorphic person would be: o Strongly built o Broad muscular chest and shoulders o Very muscular arms and legs o Little body fat o In general, mesomorphs rank high on strength, endurance, power and agility -The calculation for the mesomorph rating is based on the measurements of: o Height o Breadths of the humerus and femur o Girths of the biceps (flexed and relaxed) and calf o The girths are corrected for body fat using the skinfold measure -Typical sports; o Gymnastics o Divers o Body builders o Weightlifters o Sprinters and Hurdlers o Jumpers o Pole Vault o Shot put & discus
What would someone with an endomorph somatotype look like, what are the calculations for the ectomorph rating based off and what are the typical sports they play?
-An endomorphic person characteristic includes;
o Stocky
o Large round body
o Short thick neck
o Short arms and legs
o Tendency to store body fat
o Sports people tend not to be in this category, being either more mesomorphic or ectomorphic
o Still, it is possible that someone who is rated as an endomorph can modify their rating though diet and exercise to become more mesomorphic.
-The calculation for the endomorphy rating is based only on;
o The sum of 3 skinfolds (triceps, subscapular, supraspinale), corrected for height.
o Therefore, the higher the skinfolds, the higher your endomorphy score
-Not many sports require an endomorphic body type
-Some individuals may not look like the typical athlete but are ‘sport fit’ for their particular sport
What is puberty?
-Puberty = the period of time in which secondary sex characteristics develop and a child is transformed into a young adult
What is puberty characterised by>
o Accelerated body growth
o Rapid growth of the gonads
o Increased production of gonadal hormones
o External genital development in boys
o Breast development and menarche in females
o Pubic hair in both sexes
= Attainment of the capacity to procreate
What is low throughout childhood and infancy, whats it due to and what occurs during puberty?
-The hypothalamic-pituitary-gonadal axis secretions throughout Infancy and Childhood are low
o Possibly due to inhibition of neurons = low GnRH
-During puberty there is a marked increase in production of sex steroids/hormones
o GnRH = increase in LH and FSH
What hormones do the ovaries secrete and what do they do?
Ovaries secrete:
- Estrogen (feminizing hormone)
- Growth of ovaries and secondary sex characteristics
- Stimulates GH = increase in height and pelvic widening
- Stimulates fat deposition on the hips, thighs, buttocks and breasts
- Supresses FSH and LH
- Progesterone
- Acts on the uterus to prepare for fertilization
- Supresses FSH and LH
- Inhibin – supresses FSH
What is thelarche, pubarche and menarche?
-Thelarche = Breast Development
o Formation of lobules and ducts by estrogen, progesterone and prolactin
o Completion by glucocorticoids and GH
o Adipose tissue and fibrous tissue enlarge the breast
-Pubarche = Pubic and axillary hair growth
o Stimulated by androgens from the ovaries and adrenal cortex
-Menarche – 1st episode of menstrual bleeding
o Occurs between age 11 and 16
o Less that 17% body fat can delay this event
-Consider dancers and gymnasts
Describe follicle development
-Gamete = sex cells (sperm cell or oocyte)
-The number of primary oocytes females are born with is the maximum they will ever have
-From birth to puberty this amount reduces
-Only 400 will mature to secondary follicles and be released
-Birth to Puberty
o Primary Oocyte -> Primordial follicle
What does puberty begin with?
- Growth of Granulosa cells = Primordial follicle -> Primary follicle
- Cyclical hormonal changes = Primary follicle -> Secondary follicle
- Secondary follicle continues to enlarge -> Mature follicle
What is ovulation, what happens to ovulation during pregnancy and what happens when there is no fertilisation?
-Ovulation = the secondary Oocyte is released
-Fate
o Pregnancy
-Remaining granulosa cells corpus luteum cells
-Secretes progesterone and small amounts of estrogen
-Remains active throughout pregnancy
o No fertilization
-Corpus Luteum remains active for 10-12 days then degenerates in to corpus albicans
How long is a typical menstrual cycle?
-Typically, a 28-day cycle
What is the follicular and luteal phase?
-Follicular Phase o Development of follicles o Proliferation Phase -Of the Uterine mucosa -Luteal Phase o Existence of the corpus luteum o Secretory Phase -Maturation and secretion by uterine glands
Describe the ovarian cycle
-Events prior to ovulation =
-GnRH secretion =
o Increase FHS – stimulates the granulosa cells
o Increase LH – stimulates the theca interna cells
= follicle maturation
How do follicles secrete oestrogen?
-LH stimulates Theca interna cells to secrete androgens
-FSH stimulates granulosa cells to convert androgens to estrogen
Also
-LH stimulates the granulosa cells to produce progesterone converted to androgens by theca interna cells converted to estrogen by granulosa cells
o = increased amounts of estrogen prior to ovulation
-Inhibin = Decrease in FSH
-Increased estrogen = +ve feedback on LH and FSH = LH and FSH surge
-LH surge initiates ovulation + generation of corpus luteum
-After ovulation = Decrease estrogen
-Corpus luteum secretes progesterone = Increase in levels
o Progesterone and estrogen provide – ve feedback on GnRH = Decrease in LH and FSH
-No fertilization = degeneration of the corpus luteum
o = Decrease in estrogen and progesterone
o = menses
Describe the uterine cycle
-Changes in the endometrium of the uterus
o Primary purpose to prepare lining of the uterus to create a suitable environment for a fertilized egg
-After menses the remaining Endometrium epithelial cells of the uterus begins to proliferate (divide and replace old cells)
o Caused by estrogen
-Also increases progesterone receptors
-Cells become columnar and create folds = tubular spiral glands
-Spiral arteries project and supply nutrients
-7 days after ovulation the uterus is prepared
-Progesterone from the corpus luteum causes endometrium cells to become secretory
-No fertilization = degeneration of corpus luteum = low levels of estrogen and progesterone = degeneration of lining
-Spiral arteries constrict due to low progesterone = arteries become ischemic and necrotic = base of spiral glands dies
When does puberty occur in males and what does it increase in males?
-12-14 years of age
-Before puberty small amounts of testosterone inhibits GnRH
-Puberty = Increase in GnRH
o Increase in FSH and LH
o Testosterone still provides negative feed-back to hypothalamus but doesn’t completely inhibit
o Inhibin inhibits FSH
What is testosterone responsible for in puberty for males?
-Maturity of the male genitals
-Sperm cell production
-Hair growth
-Skin to become rougher and darker
-Increases Sebaceous gland secretion
-Hypertrophy of the Larynx and change in voice
-Simulates metabolism
o Higher rate compared with females
-Increases erythropoietin production = increase in RBC
-Greater % of body weight is muscle mass compared with females
-Rapid bone growth = increased height
o Stimulates the ossification of epiphyseal plate = reach maximum height quicker
What are the hormonal differences in males and females?
-Males = high levels of androgens and low levels of estrogen
Opposite for females
-Male hormones are secreted continuously and simultaneously whereas females have a more cyclical and sequential secretion
How does stroke volume change are we grow?
-SV increases as we grow o Pre-adolescent growth spurt = 40 ml o Growth spurt = 60 ml at rest o Untrained adult male = 70-80 ml o Trained aerobically = 100-110 ml o During exercise -Untrained = 110-120 ml -Trained = 200 ml (ave = 150-170ml)
How does heart rate change as we grow?
-Heart Rate decreases as we age o Decline by 50% from birth to maturity o Late adolescents -Males = 57-60 bpm -Females = 62-63 bpm o Young adulthood -20 yrs = 75-79bpm o Max HR o Decline in maximal HR ~0.8 beats/min/year independent of gender o Max HR = 220-age
What is cardiac output as an adult?
-Cardiac output
o Adults at rest = 5 L
How does VO2 max change as we grow?
-VO2 max (maximal oxygen consumption)
o Greater increase in males at puberty due to increase in size (muscle mass)
o Early decline in females values due to the increase in fat, and lesser degree of muscle development in the lower extremities
