L7 - Hormones and sex 25/11 SLIDE 31 - 39 REDO Flashcards
Understand the importance of hormones in brain-body communication Understand the differences between chromosomal sex, phenotypic sex, and gender Understand the key principles underlying the determination of chromosomal and phenotypic sex Understand some of the evidence relating to differences between male and female brains and the problems that have affected research in this area over the years (30 cards)
What is a hormone?
A signalling molecule
How are hormones transported?
Between organs of the body by the vascular system
What are hormones essential for?
The regulation of development, physiology and behaviour
What are hormones produced by?
Many organs of the body (the endocrine system), with receptors similarly located in many places
How are hormones controlled?
Under some level of ‘master control’ by the brain, although this itself is set within a complex feedback architecture thus undermining a simple concept of a control hierarchy.
What do hormones do?
REGUALTE
What do hormones do alongside neurotransmitters?
Underpin signalling within brain-body systems that act to maintain a desired state in terms of behaviour or physiology
What is the speed of neurotransmitters and hormones?
NTs are fast acting (onset), whereas hormones are slow acting (onset)
What distances do hormones and NTs act over?
NTs - short distances, H - long distances
What is the travel pattern of NTs and hormones?
NTs - restricted to nerve pathways. H - travel anywhere via circulatory system
What is the duration of action for hormones and NTs?
NTs - relatively short duration of action, H - relatively long
What action do NTs and hormones have?
NTs - digital action, via neuronal signalling, and tends to have more targeted actions. H - analogue action. continuously variable, tends to have more diffuse actions
Describe how hormones travel?
Secreted by endocrine gland - hormone travels through blood vessel - has a target cell with a specific receptor.
What is the hypothalamus known as/
The master controller.
Write down the flowchart of how the hypothalamus works. SLIDE 12 L7
Contextual information - cerebral cortex, amygdala, hippocampal information (context around you, information in the body).
–>
hypothalamus
(Compares input to biological set points)
^^^
Sensory inputs (Visceral and somatic sensory pathways, chemosensory and humoral signals)
Anterior pituitary hormones
Hormones responsible for the reproductive system, Hormones responsible for milk production, Hormones responsible for metabolism.
In the anterior pituitary, one hormone is released by the hypothalamus which causes another hormone to be released by the pituitary. TWO STEP PROCESS.
Posterior pituitary hormones
Released directly by pituitary, simpler process
What do hormones do??
Regulate physiology - across the whole body in accordance with motivational states such as arousal, aggression, hunger, fear, fatigue.
Regulate many processes including digestion, metabolism, respiration, tissue function, sensory perception, sleep, excrection, lactation, growth and development, movement, reproduction.
What is chromosomal sex?
Most humans have 22 pairs of autosomes and one pair of allosomes. Auto = like one another. Allo = not comparable.
Differences in the allosome pair as associated with biological aspects f phenotypic sex. and thus the 23rd pair is referred to as sex chromosomes.
Has historically been considered to define phenotypic sex and even gender, but this can/should be questioned.
FIXED
What is phenotypic sex?
Refers to internal and external genitalia, secondary sex characteristics.
XX genotype - ovaries, oviducts, uterus, cervix, clitoris, labia, vagina.
XY genotype - testicles, epididymis, vas deferens, seminal vesicles, penis, scrotum.
Often incorrectly used interchangeably with notion of gender, and can heavily influence perceptions thereof
MODIFIABLE
What is gender?
An individuals subjective perception of their sex.
Can be considered as emerging from self-appraisal in the context of social or cultural norms
Genetic and biological contributions to gender identity are complex, but probably important too.
CONSTRUCTED
What is Turner syndrome?
XO - missing X chromosome, affects females
Girls with Turner syndrome tend to be shorter in height and have impaired ovary function.
The ovaries produce two sex hormones (oestrogen and progesterone) - reduced levels of these lead to under development of secondary sex characteristics - so TS is often diagnosed at puberty
Infertility
Treatment - ovaries and progesterone
Klinefelter’s syndrome
XXY - extra X chromosome, affects male. XXXY also possible
Boys with KS tends to be taller in height and have impaired testicular function
The testicles produce the sec hormone testosterone, reduced levels of this lead to under developmental of secondary sex characteristics, so often more evidence at puberty. Infertility. Treatment is testosterone.
Can also results iin language problems, reading difficulties, delayed motor development. Reduced facial and obdy hair, breast development.
XYY syndrome
Extra Y chromosome. affects males.
Usually taller than XY males, risk of learning development problems, but symptoms usually mild. Most people are never diagnose. Normal fertility, treatment - supported learning.
