L7 - Hormones and sex 25/11 SLIDE 31 - 39 REDO

Question 1

What is a hormone?

Answer 1

A signalling molecule

Question 2

How are hormones transported?

Answer 2

Between organs of the body by the vascular system

Question 3

What are hormones essential for?

Answer 3

The regulation of development, physiology and behaviour

Question 4

What are hormones produced by?

Answer 4

Many organs of the body (the endocrine system), with receptors similarly located in many places

Question 5

How are hormones controlled?

Answer 5

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.

Question 6

What do hormones do?

Answer 6

REGUALTE

Question 7

What do hormones do alongside neurotransmitters?

Answer 7

Underpin signalling within brain-body systems that act to maintain a desired state in terms of behaviour or physiology

Question 8

What is the speed of neurotransmitters and hormones?

Answer 8

NTs are fast acting (onset), whereas hormones are slow acting (onset)

Question 9

What distances do hormones and NTs act over?

Answer 9

NTs - short distances, H - long distances

Question 10

What is the travel pattern of NTs and hormones?

Answer 10

NTs - restricted to nerve pathways. H - travel anywhere via circulatory system

Question 11

What is the duration of action for hormones and NTs?

Answer 11

NTs - relatively short duration of action, H - relatively long

Question 12

What action do NTs and hormones have?

Answer 12

NTs - digital action, via neuronal signalling, and tends to have more targeted actions. H - analogue action. continuously variable, tends to have more diffuse actions

Question 13

Describe how hormones travel?

Answer 13

Secreted by endocrine gland - hormone travels through blood vessel - has a target cell with a specific receptor.

Question 14

What is the hypothalamus known as/

Answer 14

The master controller.

Question 15

Write down the flowchart of how the hypothalamus works. SLIDE 12 L7

Answer 15

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)

Question 16

Anterior pituitary hormones

Answer 16

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.

Question 17

Posterior pituitary hormones

Answer 17

Released directly by pituitary, simpler process

Question 18

What do hormones do??

Answer 18

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.

Question 19

What is chromosomal sex?

Answer 19

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

Question 20

What is phenotypic sex?

Answer 20

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

Question 21

What is gender?

Answer 21

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

Question 22

What is Turner syndrome?

Answer 22

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

Question 23

Klinefelter’s syndrome

Answer 23

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.

Question 24

XYY syndrome

Answer 24

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.

Question 25

What do these conditions teach us about the function of sex chromosomes?

Answer 25

Two X chromosomes are important for the full development of female biological sex characteristics
If one is missing, there is underdevelopment of these aspects.
An XY chromosome must be present for the full development of male biological sex characteristcs
ONLY Y CHROMOSOME NOT POSSIBE.
The X chromomse contains 1500 genes, whereas Y only contains 90.
X contains much information important for general development and survival. Y mainly contains genes that signal for male gonadal development and sperm cell function.

Question 26

What is the SRY gene responsible for?

Answer 26

Thought to be important for the diversion toward male biological development in utero - when the fetus is around 6-8 weeks old.

Question 27

Why do men have nipples?

Answer 27

Nipples are made before the SRY gene activates
Probably evolutionary baggage
As the genetic blueprint evolved (which includes differentiation of the sex chromosomes) no strong pressure to ‘drop’ them from the main body plan as part of an additional Y chromosome instruction

Question 28

Chromosomal testing to determine male/female

Answer 28

In 1992 the International Olympic Committee implemented testing for presence of SRY gene in order to determine whether athletes were male or female

Athletes with an SRY gene were not permitted to compete as females

It was later shown that the 8 self-declared female athletes who had been shown to have an SRY gene in the 1996 Olympic in fact had an insensitivity to androgen (of which testosterone is a form)

They were thus phenotypically female, giving them no advantage over other female competitors

This chromosomal screening was eliminated in 2000 and replaced with hormone based testing

There has been an increase in debate recently on this topic, including in relation to transgender athletes

Question 29

What are gonads?

Answer 29

It is these that usually govern the development of secondary sex characteristics, usually considered a key part of phenotypic sex.