L8 Flashcards
(146 cards)
1
Q
What is a key characteristic of hydrophilic hormones regarding solubility?
A
Water-soluble
2
Q
Can lipophobic hormones cross plasma membranes?
A
No.
3
Q
Give an example of a hydrophilic hormone.
A
Peptide hormone.
4
Q
What is required for hydrophobic hormones to travel in the bloodstream?
A
Carrier proteins.
5
Q
Are steroid hormones water-soluble?
A
No.
6
Q
What is another term for lipid-soluble?
A
Lipophilic.
7
Q
What type of hormones are thyroid hormones?
A
Hydrophobic.
8
Q
What is another term for not lipid-soluble?
A
Lipophobic.
9
Q
What is the role of carrier proteins?
A
Transport hydrophobic hormones.
10
Q
Can hydrophobic hormones readily cross the plasma membrane?
A
Yes.
11
Q
How do hydrophilic hormones leave the cell?
A
Exocytosis.
12
Q
Are hydrophobic hormones synthesized in advance?
A
No, on demand.
13
Q
How are hydrophobic hormones transported in the blood?
A
Bound to carrier proteins.
14
Q
How are hydrophilic hormones transported in the blood?
A
Dissolved.
15
Q
How do hydrophobic hormones get released?
A
Diffusion.
16
Q
How are hydrophilic hormones synthesized?
A
In advance, stored.
17
Q
What is the membrane solubility of hydrophilic hormones?
A
Not lipid soluble.
18
Q
What is the membrane solubility of hydrophobic hormones?
A
Lipid soluble.
19
Q
Why are hydrophobic hormones not easy to store?
A
They leak out.
20
Q
How do hydrophilic hormones dissolve in blood?
A
Quickly.
21
Q
What are the three main types of hormones?
A
Peptide, steroid, amine.
22
Q
What are peptide hormones made of?
A
3 or more amino acids.
23
Q
From what molecule are steroid hormones derived?
A
Cholesterol.
24
Q
From what are amine hormones derived?
A
Single amino acids.
25
Are steroid hormones hydrophobic or hydrophilic?
Hydrophobic and bulky
26
What is the transport method for steroid hormones in the blood?
Bind to transport proteins.
27
What are some examples of steroids?
Sex steroids (estrogen) and cortisol
28
What are some examples of monoamines?
Catecholamine (epinephrine), thyroxine
29
What is an example of a peptide hormone?
Insulin
30
How are monoamines and peptides transported?
Both mix with blood easily
31
What are peptide/protein hormones made of?
Linked amino acids.
32
Are peptide/protein hormones made in advance or on demand?
Made in advance.
33
How are peptide/protein hormones synthesized?
Like secreted proteins.
34
Where are peptide/protein hormones stored?
In vesicles.
35
How are peptide/protein hormones released?
By exocytosis.
36
Are peptide/protein hormones water-soluble?
Yes (dissolve in blood plasma).
37
What is the half-life of peptide/protein hormones in plasma?
Short.
38
Where do peptide/protein hormones bind?
Membrane receptors.
39
Give an example of a peptide/protein hormone.
Glucagon.
40
What is mRNA translated into?
A long protein product.
41
What is the initial protein product called?
Preprohormone (a lot of additional sequences).
42
What does the cleavage of the signal sequence result in?
A prohormone (pinched off the ER and further processed in golgi).
43
What cleaves the prohormone into active hormones?
Specific enzymes.
44
What is the result of post-translational processing?
Biologically active peptide.
45
What is contained in a single preprohormone?
Several copies of the same hormone or one than one type of hormone.
46
What determines the active peptides released from a preprohormone?
Specific proteolytic processing enzymes.
47
What is the prohormone?
A gene that eventually encodes for a protein to be made, which encodes for more than one type of hormone.
48
What is the importance of cell type in hormone cleavage?
Different cell types have different enzymes.
49
What type of bonds are formed during peptide/protein hormone processing?
Disulfide bonds.
50
What part of the proinsulin molecule is cleaved when insulin is ready to be released?
C-peptide.
51
What is the state of insulin after the C-peptide is cleaved?
Active.
52
What is the initial molecule in the formation of insulin?
Proinsulin.
53
What is the significance of cleaving the C-peptide?
Releases active insulin.
54
Are steroid hormones stored in vesicles?
No.
55
How are steroid hormones released from the cell?
Simple diffusion through the plasma membrane.
56
How are steroid hormones transported in the blood?
Bound to carrier proteins.
57
Where do steroid hormones typically find their receptors?
Cytoplasm or nucleus.
58
What determines the type of steroid hormone produced?
Enzymes present in the cell.
59
Why can't steroid hormones be stored in vesicles?
They can cross through lipids and leak through.
60
What determines the type of hormone made?
Enzymes present in the cell
61
What do ovaries have that helps create estrogen?
Different enzymes
62
What portions do the enzymes add or take out to create estrogen?
Certain portions of the molecule
63
What hormones can the adrenal cortex create?
Aldosterone and cortisol
64
What are amine hormones synthesized from?
Tryptophan or tyrosine
65
What is a tryptophan derivative?
Melatonin
66
What does melatonin behave like?
Peptides or steroids
67
What are tyrosine derivatives?
Catecholamines and thyroid hormones
68
What do catecholamines behave like?
Peptides
69
What do thyroid hormones behave like?
Steroids
70
What is melatonin known as?
Darkness hormone
71
When is melatonin secreted?
At night
72
Where is melatonin made?
Pineal gland
73
What is melatonin involved in transmitting?
Light-dark cycles
74
What does melatonin govern?
Biological clock
75
What is another effect of melatonin?
Immune modulation and Anti-oxidant
76
What does melatonin control?
Circadian rhythm
77
What are tyrosine derivatives?
Hormones synthesized from the amino acid tyrosine
78
Name two categories of tyrosine derivatives.
Catecholamines and thyroid hormones
79
What is the role of the adrenal gland in relation to tyrosine?
It modifies tyrosine to create dopamine.
80
What is the function of the thyroid gland in relation to tyrosine?
It uses specific enzymes to create thyroid hormones
81
What is the relationship between tyrosine and dopamine?
Dopamine is created by modifying tyrosine in the adrenal gland
82
Where are catecholamines synthesized?
In the adrenal medulla
83
How are catecholamines stored before release?
In vesicles
84
How are catecholamines released?
Via exocytosis
85
Are catecholamines lipophobic or lipophilic?
Lipophobic
86
How do catecholamines interact with target cells?
They bind to membrane receptors
87
What is the starting material for catecholamine synthesis?
Tyrosine
88
What is the cortex's function in the adrenal gland?
It has different functions than the medulla.
89
How do endocrine cells initiate hormone release?
By directly sensing stimuli
90
Name four types of stimuli that can trigger hormone release.
Metabolites, hormones, neurohormones, neurotransmitters
91
Give an example of a stimulus and the hormone it triggers.
Rising glucose levels stimulate pancreatic β cells to release insulin
92
What needs to happen for hormones to be released?
A number of stimuli need to come into play
93
What is the direct action of endocrine cells?
To sense stimuli and secrete hormones
94
How do stimuli change membrane potential?
Through ions passing in and out.
95
What ion's level increases in the cytosol?
Calcium (Ca2+).
96
What cellular activity can stimuli alter?
Enzymatic activity.
97
What transport process can be increased by stimuli?
Hormone substrate transport.
98
What genetic process can be altered?
Gene transcription.
99
What is promoted in the endocrine cell?
Survival and growth.
100
What is the overall effect of these intracellular pathways?
Hormone release.
101
Are hormones continuously released?
Yes.
102
What is the main function of these stimuli?
To trigger hormone release.
103
How do stimuli affect gene transcription?
By altering genes coding for hormones or enzymes.
104
Where is insulin stored in the beta cell?
Inside vesicles.
105
What receptor does glucose bind to?
Glu2 receptor.
106
What process increases ATP levels?
Glycolysis and respiration.
107
What channels are inhibited by ATP?
K+ channels.
108
What happens to the cell membrane?
It becomes depolarized.
109
What channels open due to depolarization?
Voltage-gated calcium channels.
110
What ion influx triggers exocytosis?
Calcium (Ca2+).
111
What is the end result of this process?
Insulin release.
112
Is insulin made in advance?
Yes.
113
What is the role of calcium in insulin release?
It signals vesicles to endocytose insulin.
114
What two brain structures regulate hormone release?
Hypothalamus and anterior pituitary.
115
What is the role of the hypothalamus?
Sends hormones to the anterior pituitary.
116
What is the role of the anterior pituitary?
Secretes its own hormones.
117
Where do anterior pituitary hormones travel?
To target tissues.
118
What provides negative feedback?
Peripheral gland hormones.
119
Where does the peripheral gland send feedback?
To the anterior pituitary and hypothalamus.
120
What is the role of the hypothalamus in hormone release?
Sends hormones to the anterior pituitary
121
What does the anterior pituitary secrete in response to hypothalamic hormones?
Its own hormones
122
Where do anterior pituitary hormones travel?
To target tissues (periphery)
123
What does the peripheral gland secrete in response to anterior pituitary hormones?
Its own hormones
124
What provides negative feedback to the anterior pituitary and hypothalamus?
Peripheral gland hormones
125
Where does the anterior pituitary send direct negative feedback?
To the hypothalamus
126
What is the first step in the Hypothalamic-Pituitary Regulation?
The hypothalamus sends a hypothalamic hormone to the anterior pituitary
127
What is the second step in the Hypothalamic-Pituitary Regulation?
The anterior pituitary secretes its own anterior pituitary hormone
128
What is the third step in the Hypothalamic-Pituitary Regulation?
The anterior pituitary hormone travels to target tissue
129
What hormones are released from the hypothalamus?
Releasing and inhibiting hormones
130
Name an anterior pituitary hormone that targets the adrenal cortex.
Cortisol
131
What type of hormones are estrogens and testosterone?
Anterior pituitary hormones
132
What are the two different tissues that make up the pituitary gland?
Anterior and posterior pituitary
133
Which part of the pituitary gland is not able to produce hormones?
Posterior pituitary
134
What is the function of the posterior pituitary?
It can release hormones
135
What is the function of the anterior pituitary?
It is an endocrine gland
136
What is the target organ of prolactin?
Mammary glands
137
What is the target organ of thyroid hormones?
Thyroid
138
What is the target organ of insulin-like growth factors?
Musculoskeletal system
139
What are most cells sensitive to?
More than one hormone
140
What are synergistic effects?
Multiple hormones act together for a greater effect
141
Give an example of synergistic effects.
FSH and testosterone on sperm production
142
What are permissive effects?
One hormone enhances the target organ’s response to a second later hormone
143
Give an example of permissive effects.
Estrogen prepares uterus for action of progesterone
144
What are antagonistic effects?
One hormone opposes the action of another
145
Give an example of antagonistic effects.
Insulin lowers blood glucose and glucagon raises it
146
What is the combined effect of glucagon, epinephrine, and cortisol on blood glucose levels?
Much greater than each individually (Synergistic)
