1
Q
What do glands do?
A
They produce chemicals called hormones that affect cells in other parts of the body
2
Q
In what conditions do hormones work?
A
They work in very low concentrations
3
Q
Endocrine Hormones
A
a type of hormone secreted into the blood from glands
4
Q
Examples of non-target hormones
A
- growth hormones (or somatotropin)
- insulin
- epinephrine (or adrenaline)
5
Q
Examples of hormones that target particular tissues
A
- parathyroid hormone
- gastrin
6
Q
Growth hormone’s other name
A
somatotropin
7
Q
What are growth hormone’s responsible for?
A
They are responsible for growth, cell reproduction and regeneration
8
Q
What does insulin do?
A
regulates/lower blood sugar by increasing glucose permeability
9
Q
Epinephrine’s other name
A
adrenaline
10
Q
When is epinephrine produced?
A
It is produced during times of stress
11
Q
Parathyroid Hormone
A
regulates calcium levels in the body
12
Q
Gastrin
A
stimulates cells in the stomach to make digestive enzymes
13
Q
What do the nervous and endocrine systems have in common?
A
They are both responsible for controlling organs and tissues in the body
14
Q
What differentiates the nervous and endocrine systems?
A
The nervous system acts faster and the endocrine system maintains control over a long duration.
15
Q
How do hormones regulate metabolism?
A
They speed up or slow down certain processes in the body
16
Q
What allows a cell to detect one hormone but not another?
A
a cell must have the correct receptor to respond to a hormone.
17
Q
What are the two main types of hormones?
A
steroid hormones and protein hormones
18
Q
Steroid hormones
A
These hormones are soluble in fat, not water because they are composed of complex rings of carbon, hydrogen, and oxygen
19
Q
Why does the composition of steroid hormones make them soluble in fats
A
The carbon and hydrogen make them hydrophobic. Since fats are also hydrophobic and like dissolves in like, they are able to dissolve in fats.
20
Q
What is capable for steroid hormones because of their hydrophobic nature?
A
They can diffuse through the capillaries into cells (through the cell membrane made of a phospholipid bilayer) and into the cytoplasm
21
Q
Examples of steroid hormones
A
- male/female sex hormones
- cortisol
22
Q
Where are steroid hormone’s receptor molecules found?
A
They are found in cytoplasm
23
Q
Hormone-Receptor Complex
A
Is made when steroid hormone binds on to its receptor
24
Q
What happens after the hormone-receptor complex is made?
A
It moves into the nucleus and attaches to a gene segment on the DNA (or chromatin), activating mRNA transcription
25
What happens to the gene segment the hormone-receptor attaches to
ribosomes will then make the specific protein coded by the gene
26
Protein hormones
soluble in water because they are composed of chains of amino acids
27
Examples of protein hormones
- insulin
- growth hormones
28
How does the amino acid structure in protein hormones allow for it to be soluble in water?
hydrophilic (polar or charged) side chains interact with water
29
Why don't protein hormones go into the cell directly and what does this imply about their hormone?
They can't go in because they are hydrophilic. This means that their hormone is not found in the cell
30
Where are the protein hormones in the context of the cell
They are attached to the cell membrane.
31
Adenylyl Cyclase
This is an enzyme that is made after the protein hormone- receptor complex is made which activates the enzyme's production
32
What does adenylyl cyclase do?
It causes cell to convert ATP into AMP (or more accurately cAMP)
33
What is AMP in the concept of adenylyl cyclase?
It is cyclic adenosine monophosphate
34
What is the purpose of AMP molecule?
It acts like a messenger that activates enzymes in the cytoplasm to perform their normal functions
35
Pituitary Gland
controls the other endocrine glands
36
What's another name for pituitary glands?
master gland
37
How do pituitary glands look like?
They are a sac-like structure connected to the hypothalamus
38
What is the purpose of the hypothalamus?
an area of the brain that's responsible for homeostasis
39
What does the hypothalamus-pituitary complex show?
shows how the nervous and endocrine system come together
40
What are the respective roles of pituitary glands and hypothalamus in the hypothalamus-pituitary complex?
(endocrine system) Pituitary Gland- produces and stores hormones
(nervous system) Hypothalamus- stimulates the release of pituitary hormones using nerves
41
How many lobes are pituitary glands made up of and what are they?
2 lobes
- posterior lobe
- anterior lobe
42
Posterior Lobe
stores and releases hormones such as oxytocin and ADH which are produced by the hypothalamus
43
What is the purpose of oxytocin
to initiate uterine contractions during childbirth
44
What is the purpose of ADH
it is used to regulate body water if in the kidney
45
How do hormones get to the pituitary gland?
They get there through special nerve cells originating in the hypothalamus
46
Anterior Lobe
produces its own hormones (unlike the posterior lobe)
47
The purpose of nerves in posterior lobes is to transport hormones to the glands. How about the purpose of nerves in anterior lobes?
The hypothalamus has many nerves connecting to the anterior lobe but they don't release their hormones to the anterior lobe, rathe they release hormones into the blood that will then reach the pituitary gland
48
What is the purpose of hormones made in the hypothalamus for anterior lobes
They are specifically made to activate cells in the anterior lobe so that pituitary hormones can be released into the blood and affect target tissue in the body
49
What hormones does the anterior lobe release
GH, PRL (prolactin), FSH & LH, TSH, ACTH
50
What are FSH & LH?
reproductive-stimulating hormones)
51
What is TSH?
thyroid stimulating hormones)
52
What is ACTH?
stimulates the adrenal cortex
53
What are the two types of cells that a pancreas has?
- cells that produce digestive enzymes
- cells that produce hormones
54
Where are cells that produce hormones found?
They are in the islets of Langerhans
55
What do the islets of Langerhands contain
They contain alpha cells and beta cells
56
What are the respective roles of alpha and beta cells
Alpha cells: produce glucagon
Beta cells : produce insulin
57
When is insulin released?
release in response to increasing blood sugar to cause cells of the muscles, live and other organs to become more permeable to glucose/sugar
58
Permeable
allowing certain molecules to pass through
59
How does insulin reduce sugar levels?
It helps store glucose in the form of glycogen which decreases blood sugar
60
Glucagon
causes an increase in sugar levels by causing glycogen to be converted back into glucose, which is released in the blood
61
What is the correlation between glucagon and insulin
Insulin works to reduce sugar levels by converting glucose into glycogen and is stored in organs
Glucagon works to increase sugar levels by converted glycogen back into glucose and is released back into the blood
62
Why do insulin and glucagon create a negative feedback system?
Whenever blood glucose deviates from the normal range, the body produces a hormone that pushes it back toward normal by reversing the direction of the change.
GOAL IS TO MAINTAIN HOMEOSTASIS
63
Hyperglycaemia
when blood sugar rises sharply after meals
64
What is the cause of hyperglycaemia?
insufficient production or use of insulin
65
Which people have hyperglycaemia?
people with diabetes
66
Why do people with diabetes have low energy levels?
If insulin levels drop, muscle and fat cells are less permeable to glucose --> reduced sugar uptake --> sugar stays in blood
67
Where are adrenal glands found?
Adrenal glands are found above the kidney
68
How many glands are inside the adrenal gland and what are they?
Adneral gland is made up of two glands
- adrenal medulla
- adrenal cortex
69
Adrenal Medulla
regulated by the nervous system for short-term stress
70
Where is the adrenal medulla found?
It is considered the inner gland
71
What 2 hormones does the adrenal medulla produce?
- epinephrine (adrenaline)
- norepinephrine (noradrenaline)
72
When are the hormones that the adrenal medulla make released?
They are secreted into the blood during stressful situations.
73
What is the result of hormones made by adrenal medulla being released?
they cause blood sugar rises from glycogen breakdown
- they also cause increased heart rate, breathing rate, and metabolism
It signals the pancreatic alpha cells to secrete more glucagon, which then causes the liver to release stored glucose into the bloodstream.
74
How does the body deal with the effects of short term stress
the blood vessels dilate (become wider) to increase blood flow along with dilated pupils
More oxygen + more blood flow + more glucose → stronger, faster reaction
75
Adrenal cortex
regulated by hormones for long-term stress
76
Where is adrenal cortex located?
its the outer gland
77
What are the three types of hormones that adrenal cortex produces?
- glucocorticoids
- mineralocorticoids
- sex hormones (small amount)
78
When are the hormones in the adrenal cortex released?
They are released when the hypothalamus sends a releasing hormone to the anterior lobe of the pituitary --> ACTH is released --> ACTH targets cells in the adrenal cortex to produce hormones
79
Glucocorticoids
associated with blood sugar levels as it increases amino acid levels in the blood which in turn gets converted into glucose in the liver, raising blood sugar levels through a process called gluconeogenesis
80
What is an important glucocorticoid
cortisol with helps body recover from stress
81
What happens to the extra amino acids from increase amino acid levels by glucocorticoids?
They are used to help repair damage
82
What's another source of energy?
Provided by fats by breaking them down into fatty acids
83
How are cortisol levels regulated?
As cortisol levels rise, the hypothalamus and pituitary (specifically the anterior lobe) eventually cause the levels to fall by decreasing the production of regulatory hormones (like ACTH)
84
Aldosterone
an important example of mineralocorticoid
85
What does aldosterone do?
It increases sodium retention and thus water reabsorption in the kidney which maintains body fluid levels
86
Where are thyroid glands located?
Base of neck (in front of the trachea)
87
What do thyroid glands do?
secrete thyroxine (T4) and triiodothyronine (T3)
88
What is the point of thyroid glands making T4 and T3?
It is to regulate the growth and differentiation of tissues, and body metabolism
89
Which of the two (T3 or T4) is secreted more often and what does this do?
most secretions are T4 and cause an increase in body metabolism by stimulating increased sugar utilisation by body cells
90
What do high T4 levels mean?
It means someone has a higher metabolism -->
someone is less prone to weight gain (as nutrients and sugars are oxidised at a faster rate)
and
causes them to feel warmer (cells work faster → more reactions per second → more heat is produced.)
91
What are low T4 levels associated with?
weight gain, feeling cold, muscle weakness, dry skin and hair
92
What's another name for high T4 levels
hyperthyroidism
93
What's another name for low T4 levels
hypothyroidism
94
How are thyroid hormones controlled/regulated
negative feedback mechanisms
95
What does a negative feedback system do?
the product in a chain of chemical reactions acts upon an enzyme upstream of the chain causing it to slow down, therefore controlling the amount of the end product
96
What happens if metabolic rates decrease?
receptors in hypothalamus are activated --> TRH is released --> stimulates pituitary to release TSH made in anterior pituitary --> TSH goes to thyroid --> releases T4 --> T4 increases body metabolism
97
How are metabolic rates decreased?
High levels of T4 now begin to turn the pathway off --> hypothalamus produces less TRH
98
Calcitonin
hormone in the thyroid gland that absorbs calcium which makes bone cells reduce the levels of calcium in the blood
99
Why is controlling thyroid hormones considered negative feedback
High levels of the final product (T4) shut down the production of earlier hormones (TRH and TSH), keeping hormone levels stable.
100
Why are goiters produced?
They are produced when thyroid glands don't get enough iodine --> thyroid glands enlarge --> goiters
101
How are goiters are formed?
lack of iodine --> T4 production goes down --> TSH (causes the release of T4) will always be high --> TSH stimulates thyroid glands to grow --> thyroid glands are stimulated excessively --> thyroid glands are enlarged
102
How do we include iodine in our diet?
It is typically added to our table salt
103
Parathyroid Glands
They are hidden in the thyroid and there are 4
104
What do parathyroid glands do?
They control calcium levels in the blood
105
What happens when there are low calcium levels?
It stimulates the release of parathyroid hormones (PTH) because it increases calcium levels in the blood and decreases phosphate levels
106
How does PTH increase calcium levels?
It causes kidneys and the gut (digestion food) to retain calcium, while making bones release calcium because they store most of the body's calcium
107
What else do PTH do outside of increasing calcium levels?
They activate vitamin D
108
How does negative feedback work for PTH?
As calcium levels increase, pTH release is inhibited thus balancing the level of blood in calcium
109
What 2 hormones are inhibited by negative feedback
TRH- due to high levels of T4 that slow down production
PTH- due to high calcium levels
110
What is the correlation between PTH and calcitonin?
Low calcium → PTH increases
High calcium → Calcitonin increases
111
What parts the body does GH (growth hormone or somatotropin) affect?
It affects body cells, especially the cartilage and bone cells
112
How does GH affect growth
It causes growth by increasing the number and size of cells by promoting protein synthesis and inhibiting protein breakdown
113
What happens to GH as we age?
GH synthesis goes down and we start to lose muscle mass for this reason
114
Why are growth spurts often accompanied by decrease in body fat?
GH causes cells to use fatty acids as fuels (not just glucose). This causes people to lose more fat as it is used for protein synthesis
115
How does the nervous system adjust to stress?
It increases heart rate and supply muscles with more blood
116
How does the endocrine system adjust to stress?
It is slower but hormones give a more sustained response to the stimulus
117
What happens to blood sugar levels
Blood sugar levels increase because glucagon increase and insulin decreases
118
What happens to blood pressure and volume to adjust to stress?
Blood pressure and volume is raised also
119
What does the nervous system do to reduce blood flow to kidney's
activates the renin-angiotensin-aldosterone pathway
120
How is blood pressure maintained in the kidney?
Increasing Na+ absorption in the kidney --> increase fluid volume
121
How does hypothalamus react to stress
It is activated by the stressor to produce ADH which further increases water reabsorption in the nephron, retaining body fluids
122
What does emotional or mental stress do to the body
It increases the energy available, even though it won't be used
123
What is dangerous about having a lot of stress
If it prolonged increase in blood pressure, high blood glucose, and higher metabolic rates, it can cause long term problems for the body
124
Prostaglandins
hormones that have an effect in a small localised area and are absorbed rapidly by surrounding tissue
125
What is an example of what prostaglandins can do?
- They can increase blood flow to local tissues
- They can trigger the relaxation of muscles lining the pathways that supply lungs with air
126
How do the RAAS and nervous system coordinate blood flow during stress?
The nervous system redirects blood to muscles and away from kidneys, while RAAS compensates for reduced kidney blood flow by retaining water through increasing Na+ reabsorption (increase fluid volume through osmosis) and producing ADH (increase water reabsorption)
127
Where are interstitial cells of the testes found?
They are found between seminiferous cells
128
What is the purpose of interstitial cells?
They produce males hormones androsterone and testosterone
129
What 2 things are testosterone responsible for?
- stimulates spermatogenesis, which ultimately causes sperm production to take place
- responsible for secondary male sexual characteristics
130
Out of the two hormones, androsterone and testosterone, which ones is most potent and abundant?
Testosterone
131
What role do hypothalamus and pituitary gland have in male reproductive system?
they use negative feedback to control male sex hormones and sperm production in the testes
132
What does the pituitary gland do in a male?
produces and stores gonadotropic hormones
133
What are examples of gonadotropic hormones?
- follicle stimulating hormone (FSH)
- luteinising hormone (LH)
134
What is the role of follicle stimulating hormone (FSH)?
used for sperm production
135
What is the role of luteinising hormone (LH)
used for testosterone production. Testosterone also now increases sperm production as well as FSH
136
Gonadotropin-releasing hormone (GnRH)
it is what the hypothalamus secretes to activate pituitary gland to secrete FSH and LH made by anterior lobe
137
Negative feedback when testosterone levels are too high
Testosterone deactivates the hypothalamus so it won't produce as much GnRH --> less GnRH to activate pituitary gland --> lower amount of LH and FSH made --> less LH means less testosterone
138
Inhibin
a peptide hormone which is produced by Sertoli cells that also act as FSH
139
What role does inhibin play in negative feedback for FSH production
it sends negative feedback signals to the pituitary to slow down FSH production
140
Why is the female reproductive system more complicated than the male reproductive system
Rather than marking sperm cells at a constant rate, the female cycle controls one egg being released once per month, in cycles
141
Follicles
tissues in small groups found in ovaries
142
What are the two types of cells make up follicles
- primary oocyte
- granulose cells
143
Primary oocyte
undergoes meiosis 1 to produce a secondary oocyte that has 23 chromosomes and quick starts meiosis 2
144
Granulose cells
provides nutrients for the oocyte
145
What happens during ovulation?
only one follicle become dominant and reaches maturity. The primary oocyte in this follicle develops within the follicle and will be eventually ovulated from it
146
Corpus Luteum
The resulting empty follicle that forms after primary oocyte is ovulated form follicle
147
Progesterone
this is released by corpus luteum to maintain potential pregnancy
148
What happens to progesterone if pregnancy doesn't occur?
If pregnancy doesn't occur, progesterone degenerates after about 10 days.
149
How many days is the menstrual cycle
average of 28 days
150
How many phases is the menstrual cycle divided in and what are those cycles?
4 phases
- flow phase
- follucular phase
- ovulatory phase
- luteal phase
151
How long does flow phase last?
Day 1-5
152
What happens in the flow phase?
shedding of endometrium marks the beginning of the cycle
153
How long does follucular phase last?
Days 6-13
154
What happens in the follucular phase?
development of follicles in the ovary. As they develop, estrogen is secreted and will keep increasing during continued development
155
How long does ovulatory phase last?
Day 14
156
What happens in the ovulatory phase?
egg crusts from the ovary and follucular cells differentiate into the corpus lute. Estrogen levels dip a bit
157
How long does luteal phase last?
Day 15-28
158
What happens in the luteal phase?
This is where new corpus lutes develops. It secretes estrogen (goes back up) and progesterone
159
What is the role of progesterone during the luteal phase?
It is to maintain endometrium so it can prepare the uterus for an embryo
Inhibits further ovulation and prevents uterine contractions
160
What happens when progesterone levels fall
Uterine contractions begin.
Estrogen also falls
Marks the beginning of the next flow phase
161
Why would progesterone levels fall
ovum doesn't get fertilised
162
What happens when FSH is made
it is carried to the ovary to stimulte follicle development
163
In which phase are FSH extremely important and why?
In the second phase (follicular phase) because blood carries FSH secretions to ovary to make follicles
164
What does FSH do to the ovaries
It stimulates follicle development --> follciels secrete estrogen and thicken endometrium (uterine lining)
165
Why do estrogen levels dip bit by the third phase?
This is because when estrogen rises in the second phase, negative feedback causes the pituitary gland to turn off secretions of FSH --> follicular phase ends
166
How do estrogen levels also support positive feedback on top of negative feedback?
rising estrogen levels stimulates the pituitary to secrete LH and ovulation occurs which happens in the ovulatory phase
167
What results from estrogen and progesterone build up?
They work together to inhibit the release of both FSH and LH
167
How do we transition from the third stage to the fourth stage
After ovulation, follicular cells develop into corpus luteum, starting the luteal phase.
Corpus lutes recreates progestrone and estrogen --> endometrium development increases
168
When corpus lectures deteriorates what happens to estrogen and progesterone
both drop, triggering menstruation
169
Examples of male and female sec hormones being produced by each gender
- androgens (a male sex hormone) exceed the levels of estrogen
- female hormones in makes are excreted at an accelerated rate, keeping levels low
Biology
flashcards
Decks in class (12)
# Cards
-
Chapter 2- Cellular Respiration92
-
Chapter 3- Photosynthesis88
-
Chapter 4- DNA53
-
Chapter 5- Protein149
-
Chapter 6- Biotechnology92
-
Chapter 7- Excretory System170
-
Chapter 8- Endocrine System170
-
Chapter 9- Nervous System211
-
Chapter 10- Immune System122
-
Chapter 14- Population Dynamics100
-
Chapter 1- Biochemistry207
-
Chapter 1530
