Gender differences Flashcards
What happened in 60s & 70s
It became clear that gender could influence biomedical research results
Why may disease & treatment vary between genders
As diseases can affect the two differently
- Certain diseases affect one gender more than the other
How can gender be determined after death
- Women generally have bigger pelvises
- Men generally have more skeletal muscles and bigger frames
Osteoporosis
80% patients are women
Autoimmune disease
3-fold more common in women than men
Depression
2-3 times more common in women than men
Depression
- reasons why more common in women
- Possible connection to women producing less serotonin (neurotransmitter) - though some peoples doesn’t improve with antidepressants (boosts serotonin)
Other mental health diseases
Sex-based differences also present in incidence & expression of schizophrenia, PTSD, panic disorder, etc.
Potential causes of sex-based differences in physiology & disease
- Societal
- Genetic
- Effects of the sex steroids
Societal
- Lifestyle/behaviour - Some female athletes show very similar physiological traits as men
- Environmental
- Healthcare
Genetic
Linked to x- or Y- chromosome
transgender people
It can be hard to treat transgender people because some treatments are gender based and they are truly the opposite gender than is at face value
Effects of sex steroids
- Ones involved
- Androgens, estrogens and progestins
- All present in both males and females
Effects of sex steroids
- Estrogens & androgens
Physiologically important in both males and females
Sex hormones & life stages
- Prenatal development
Sexual differentiation - all start off as female in womb
Maturation
Child, adolescent & young adult
Other life stages
- Variation with menstrual cycle in women
- Pregnancy
Cancer
Some cancers target one gender rather than the other because of the hormones they target
Menopause
Causes abrupt drop in estrogen & progesterone
Hormones with aging
Gradual decline in testosterone with aging in both men & women
- After the menopause the difference in physiology and hormones becomes smaller, as men and women become more similar
sex based differences in body comp & structure
- Well known (stereotypes)
Men have:
- Greater bone mass
- Greater muscle mass
- Lower %bf - typically because women have higher due to reproductive system
Structural differences in M&F
- Men have bigger hearts and lungs
- Men have bigger brains
- Gastrointestinal system
Differences in ‘normal values’
- Cardiovascular
- Blood pressure
5-10mmHg higher in men than women
- Difference disappears after menopause
HR
Lower in men than age-matched women
ECG intervals
some longer in women
Renal
- Kidney filtration rate
- Slightly lower in young female than age matched men
- May decline more rapidly with age in men than women
- Men’s kidneys are generally more worn out and show more strain then womens
Liver
- Lipid metabolism
- Drug metabolism - there is a difference in the way that men and women metabolise drugs - which is why certain medications (even at the same dose) affect a man and women in completely different ways
Other difference in physiological function
- Gastrointestinal
- immune system
- kidney
- Lung
- skin
- Etc.
Heart disease
Leading cause of death in both men and women
Heart disease
- Differences between gender
- Starts 10 years later in women than men
- Difference in symptoms, progression and outcomes
Stroke
More likely in women than men
Heart size
- Men have significantly greater left ventricle mass than women as well as chamber size
- Because men have to generally pump more blood around the body due to having bigger frames
Blood pressure
Women have lower resting blood pressure
- Also have lower tolerance to shifting posture and sudden changes in position - more likely to faint
- Equal to men after menopause
Typical signals of a heart attack
- Chest discomfort/uncomfortable pressure/squeezing or pain in centre of chest
- spreading pain to one or both arms, back, jaw or stomach
- Cold sweats and nausea
Women and heart attacks
- Only 30% exhibit typical symptoms
Typical heart attack signals - women
- Shortness of breath
- nausea
- vomiting
- sleeplessness
- back pain or jaw pain
- generalized weakness
- Leads to late treatment and preventable deaths
BF
women typically have higher bf% (5-10%) and lower muscle mass than an average male
How do women metabolise carbs
Women metabolise carbs like glucose at varying rates depending where they are in their menstrual cycle
- Why women get different cravings when they are on their periods
Metabolism during endurance exercise
Females burn more fat and less carbs and protein during endurance exercise compared to males
Lung capacity
Men have larger lungs, wider airways, and greater lung diffusion capacity than women - even if normalised to height
Consequence of structural difference in lungs
Compared to young healthy males, maximal exercise capacity may be limited by pulmonary capacity in women - especially as they age
Brain circumference
12-20% larger in boys than girls
- Based on body weight at this age - if similar weight, they will have similar size of brain
head circumference
boys 2% larger than girls
Brain weight
11-12% more in men than women - heads also 2% bigger
Cognitive abilities
- Said that women are better at certain language abilities and men are better at certain spatial abilities
- Many studies have tried to find difference in R & L cerebral hemispheres to suggest male and female brains are different - however few have been found meaningful - often bad studies
Hypothalamus
preoptic area and the suprachiasmatic nucleus have clear differences in male and female brains
Preoptic area
- Difference only apparent after 4 y/o
- Area involved in mating behaviour
- Greater in volume, cross section and number of cells than in women
Suprachiasmatic nucleus
- Involved in circadian rhythms & reproduction cycles
- Shaped like sphere in men and more elongated in women
Differences in skeletons
- Men have thicker and longer limbs
- Men have bigger and longer leg bones
- Women have narrower rib cages, smaller teeth and less angular mandibles (jawbone)
- Women have less pronounced cranial features
- Women have bigger hips than men
Sex determination from skeletons
- Only can tell difference in adolescent and adult skeletons because there are far fewer sexual differences in children before puberty
- Men typically have larger muscle attachment points on their bones
Pelvis
- The great sciatic notch is wider in women than men 68degress in women, less for men
- Acetabulum (head of femur meets pubic bone) bigger and deeper in men - because men have narrow pelvis
- Sacrum straighter in females more curved in men
- Pelvic inlet is larger and more round in females - to facilitate child birth
Skull
- Chin more square in men and more pointed in females
- Forehead more slanted back on males and more rounded in females
- Men have more pronounced brow ridges
Training recommendations
Many biased against women as were developed from all-male trials
Studies and training programmes
- Females more willing to volunteer for studies involving muscle biopsies and other minor procedures
- Females more likely to follow training programmes and attend all appointments
Male v Female performance
Women not as weak as men once assumed and are quite often able to physically perform at a superior level
Women and endurance
- Females better suited to ultra-endurance sports then men
- Field-study found that women out-performed men at the 90km distance
- Whereas men were found to out perform females up to 42km, with increasing performance advantage for females above 66km
- Women can adapt more and change where they get their energy from
