Question

1.What layer of the uterus is shed during menstruation and why?

2.What is the difference between sensible and insensible water loss?

3.Where is the thirst center in the brain and how does it work to make you thirsty or not?

Answer 1

Answer

1) Endometrium is the layer of uterus that shed during menstruation.

• After ovulation, increase in progesterone hormone makes the endometrium thick for implantation of the zygote.
• If fertilization do not occur, the levels of estrogen and progesterone falls.
• This leads to shedding of the endometrial lining.

2)

Sensible water loss	Insensible water loss
This type of water loss can be easily measured. The loss of water is noticable.	This type of water loss cannot be easily measured. The water loss is not sensed by the individual.
Example : Urination, vomitting, blood loss.	Example : Water loss during respiration, water lost in feces.

3) The thirst center in the brain is hypothalamus.

• Hypothalamus contains recetors callled osmoreceptors.
• These receptors detect increased plasma osmolarity due decreased fluid volume in the body.
• Osmoreceptors initiate increase in thirst that leads to increased water intake.
• As adequate amount of water is ingested, the fluid volume is restored. This results in decrease of plasma osmolarity.
• The osmoreceptors in hypothalamus inhibit thirst sensation.