Chapter 18 - Metabolic Rate Flashcards
What is the metabolic rate?
The speed with with the body uses up the energy from food.
What increases metabolic rate?
Exercise or cold temperatures
The resting metabolic rate is sometimes called..?
The basal metabolic rate
Which organ affects metabolic rate?
Thyroid
Which hormone is produced by the thyroid?
Thyroxine
What effects is thyroxine responsible for causing?
Increasing heart rate
Increases the rate of breakdown of proteins and carbohydrates inside cells
Which mineral is required so that thyroxine can be produced?
Iodine
What causes a thyroid ‘goitre’?
Insufficient iodine in diet. The body tries to respond by producing more thyroid gland cells.
What are some of the health problems caused by too much or too little thyroxine?
Graves’ disease
Hypothyroidism
Hyperthyroidism
Hashimoto’s disease
Which organs are responsible for controlling the production of thyroxine by the thyroid gland?
The hypothalamus and the pituitary gland.
When thyroxine levels are too low, which hormones are released by the hypothalamus and the pituitary gland?
TRH and TSH
What happens when the thyroxine level is too high?
The hypothalmus and pituitary glands stop producing hormones, which in turn ceases production of thyroxine.
Where are the adrenal glands situated?
Above each kidney
When is adrenaline produced?
When the adrenal glands are stimulated by the nervous system as a result of the person expecting danger.
What does adrenaline cause?
Increased heart rate
Increased breathing rate
Promotes breakdown of glycogen into glucose to meet increased energy requirements
Diverts blood to muscles and away from non-essential areas such as digestion, achieved by widening or narrowing the blood vessels associated with those organs.
What protects the uterus?
Cervix and mucus plug
What is the uterine wall made up of?
The myometrium (muscle layer) The endometrium (lining)
Eggs inside ovaries are immature and incapable of being fertilised. Is this statement true or false?
True
How many eggs are produced during ovulation?
Usually one.
How long is an average menstrual cycle?
28 days
What falls away during menstruation?
The outer layers of the endometrium
What happens between day 1-14 of the menstrual cycle?
An egg is maturing in the ovaries.
What happens when menstruation ends?
The endometrium is rebuilt. It thickens, and an extensive blood supply is created to nourish a potential fertilised egg
Which hormone stimulates the build up of the endometrium?
Oestrogen
When is the egg released?
About 15 days before the end of the cycle.
When is fertilisation most likely?
In the 3 days following release
When does implantation of the zygote take place?
Several days after fertilisation
Which hormone causes the endometrium to remain intact?
Progesterone.
What makes progesterone?
Corpus luteum.
If the egg is not fertilised, what happens?
The corpus luteum degenerates, progesterone production stops, causing the lining to break down again.
On which day in the cycle does menstruation begin?
Day 1
What happens to oestrogen and progesterone levels at the end of each cycle?
They fall
At which point does the pituitary gland release FSH?
When the low levels of oestrogen and progesterone are detected by the pituitary gland.
What does FSH do when it reaches the ovaries?
Stimulates the maturation of follicles and the egg they contain
What produces oestrogen?
The cells of the developing follicle
Why do they produce oestrogen?
To stimulate regrow this of the uterus lining in preparation for the maturing egg
What happens when the egg is almost ready for ovulation?
It’s oestrogen production rapidly rises to peak
