APII: Endocrine System Flashcards
(88 cards)
1
Q
What two systems combine to form the ‘System of Control’?
A
Endocrine system + Nervous system
2
Q
What are the primary methods of action in the nervous system and endocrine system?
A
Action potentials for nervous system; Hormones for endocrine system
3
Q
How is the effect of the nervous system described compared to the endocrine system?
A
Localized vs. General
4
Q
Which system is characterized by very fast acting responses?
A
Nervous system
5
Q
Which system has a slower acting response?
A
Endocrine system
6
Q
What is the duration of effects for the nervous system compared to the endocrine system?
A
Very Short vs. Much longer
7
Q
What are the two types of glands in the body?
A
Exocrine and Endocrine
8
Q
What do exocrine glands do?
A
Secrete their product through a duct onto a body surface or into a body cavity
9
Q
Are there exocrine systems in the body?
A
No, exocrine glands are parts of other systems
10
Q
What do endocrine glands secrete?
A
Hormones directly into the blood without a duct
11
Q
What are hormones by definition?
A
The product of an endocrine gland
12
Q
What are prostaglandins and how do they differ from hormones?
A
Substances that act like hormones but are produced and used locally, not from an endocrine gland
13
Q
What characterizes endocrine glands in terms of tissue vascularity?
A
They are some of the most vascular tissue in the body
14
Q
What does it mean that hormones are released into the blood?
A
All body cells are exposed to all hormones
15
Q
How do cells control which hormones affect them?
A
Cells have receptor sites that hormones bond to
16
Q
What are target tissues?
A
Cells that have receptor sites for a particular hormone
17
Q
Fill in the blank: Hormones only affect cells that have _______ for that particular hormone.
A
receptor sites
18
Q
A
19
Q
What are protein hormones?
A
Proteins or protein derivatives
Most hormones are protein hormones.
20
Q
Where are the receptor sites for protein hormones located?
A
On the cell membrane
Protein hormones cannot pass through the cell membrane.
21
Q
What is the first messenger in hormone signaling?
A
The protein hormone
It activates the second messenger.
22
Q
What is the role of cyclic AMP in hormone signaling?
A
It is the second messenger that activates enzymes
This leads to changes in cellular activity.
23
Q
Why are protein hormones faster acting than steroid hormones?
A
Because the precursor molecules already exist and simply need activating
This allows for quicker responses.
24
Q
What are steroid hormones derived from?
A
Cholesterol
They are lipid derivatives.
25
Where are the receptor sites for steroid hormones located?
In the cytoplasm
## Footnote
Steroid hormones can pass through the phospholipid cell membrane.
26
What forms when a steroid hormone bonds to its receptor?
Hormone/Receptor complex (H/R complex)
## Footnote
This complex affects cellular activity.
27
What does the H/R complex do after entering the nucleus?
It has a direct effect on DNA
## Footnote
It causes production of messenger RNA (mRNA).
28
Why are steroid hormones relatively slow acting?
Because mRNA and proteins must be synthesized from scratch
## Footnote
This takes more time compared to protein hormones.
29
What is the potency of hormones?
Hormones are very potent
## Footnote
A small amount can have profound effects on the body.
30
What is the main method of hormone regulation?
Negative feedback
## Footnote
The gland is sensitive to levels of the substance that the hormone regulates.
31
What does the pancreas regulate in relation to hormone levels?
Blood glucose levels
## Footnote
It is sensitive to blood glucose levels, not insulin levels.
32
33
What happens to blood glucose levels after we eat?
Blood glucose levels rise
## Footnote
This triggers the pancreas to produce insulin.
34
What role does insulin play in glucose metabolism?
Increases cellular uptake of glucose, converts glucose into glycogen, inhibits glucose production from noncarbohydrate sources
## Footnote
When glycogen reserves are full, glucose is converted into fat.
35
How does the pancreas respond to decreased blood glucose levels?
Stops production of insulin
36
What are tropic hormones?
Hormones secreted by glands in response to other (tropic) hormones
## Footnote
Example: Gland A secretes hormone A, causing Gland B to produce hormone B.
37
What is an example of direct nervous stimulation in hormone production?
Sympathetic nervous system stimulates adrenal medulla to produce epinephrine and norepinephrine
38
What is positive feedback in the context of hormonal regulation?
A 'Snowball Effect' that amplifies a response
39
What is the pituitary gland also known as?
Hypophysis
40
How is the pituitary gland connected to the hypothalamus?
Via infundibulum
41
What is the size of the pituitary gland?
Size of a pea
42
What are the two parts of the pituitary gland?
* Anterior pituitary gland (adenohypophysis)
* Posterior pituitary gland (neurohypophysis)
43
How does the anterior pituitary gland receive signals from the hypothalamus?
Through the hypothalamic-pituitary portal system
44
What is the role of the posterior pituitary gland?
Stores and releases hormones produced in the hypothalamus
45
What is axoplasmic flow?
Flow of cytoplasm in the axon
46
Name a hormone secreted by the anterior pituitary gland.
* Growth Hormone (GH)
* Thyroid Stimulating Hormone (TSH)
* Adrenocorticotropic Hormone (ACTH)
* Antidiuretic Hormone (ADH)
47
What condition is caused by too little growth hormone during childhood?
Pituitary dwarfism
48
What is gigantism?
Excess growth hormone during childhood before growth plates have ossified
49
What is acromegaly?
Excess growth hormone after growth plates have ossified, leading to increased bone diameter
50
Who is a historical figure that may have had acromegaly?
Abraham Lincoln
51
52
What hormones does the thyroid gland produce?
Thyroxine, triiodothyronine, and calcitonin
## Footnote
Thyroxine (T4) and triiodothyronine (T3) are crucial for metabolism, while calcitonin helps regulate calcium levels.
53
Where is the thyroid gland located?
Next to the trachea, just below the larynx
## Footnote
The thyroid gland's position is critical for its function and relation to other structures in the neck.
54
What percentage of active thyroid hormone is thyroxine?
95%
## Footnote
The remaining almost 5% is triiodothyronine, both of which require iodine for synthesis.
55
What happens if there is an iodine deficiency?
Hormones cannot be produced, leading to the production of TSH and enlargement of the thyroid gland
## Footnote
The enlargement is called an iodine deficiency goiter (simple goiter).
56
What is the purpose of iodizing salt?
To prevent iodine deficiency
## Footnote
Iodine deficiency can lead to thyroid disorders, including goiter.
57
What is cretinism?
Hypothyroidism in children, resulting in severe retardation and abnormal skeletal features
## Footnote
Cretinism is a serious condition that can affect physical and mental development.
58
What is myxedema?
Hypothyroidism in adults characterized by low metabolic rate, lethargy, weight gain, and hair loss
## Footnote
Myxedema can lead to significant health issues if untreated.
59
What condition is characterized by an enlarged thyroid producing too much hormone?
Hyperthyroidism
## Footnote
Symptoms include high metabolic rate, hyperactivity, nervousness, insomnia, irritability, and chronic fatigue.
60
How does calcitonin reduce blood calcium levels?
Three ways:
* Decreases osteoclast activity
* Decreases reabsorption of calcium by kidneys
* Decreases absorption of calcium by intestines
## Footnote
This hormone plays a critical role in maintaining calcium homeostasis.
61
What are the parathyroid glands?
Four small glands on the posterior surface of the thyroid gland
## Footnote
They are essential for regulating calcium levels in the blood.
62
What hormone do parathyroid glands produce?
Parathyroid hormone
## Footnote
This hormone is the most important regulator of blood calcium levels.
63
How does parathyroid hormone increase blood calcium levels?
Three ways:
* Increases osteoclast activity
* Increases reabsorption of calcium by kidneys
* Increases absorption of calcium by intestines
## Footnote
These actions are crucial for maintaining calcium homeostasis in the body.
64
Why is calcium essential for the body?
Calcium is crucial for many body processes, not just building bones
## Footnote
Calcium ions play a vital role in muscle contraction and other physiological functions.
65
What role do calcium ions play in muscle contraction?
They are released from the sarcoplasmic reticulum, uncovering active sites on actin filaments
## Footnote
This allows myosin heads to attach and initiate contraction.
66
67
What happens when an action potential reaches a synapse?
Calcium ion gates in the presynaptic membrane open, calcium ions rush in, triggering the release of neurotransmitters.
## Footnote
This process is essential for neurotransmission and the communication between neurons.
68
What is hypoparathyroidism and its effect on blood calcium levels?
Hypoparathyroidism causes low blood calcium levels, leading to nerve excitability and spontaneous nerve impulses, stimulating muscle contraction.
## Footnote
This condition is similar in effects to alkalosis.
69
What is hyperparathyroidism and its potential consequences?
Hyperparathyroidism causes high blood calcium levels, which can lead to kidney stones and calcium deposits in abnormal locations.
## Footnote
This condition can result in various complications affecting health.
70
Where are the adrenal glands located?
One on top of each kidney.
## Footnote
The adrenal glands play a crucial role in hormone production.
71
What are the two parts of the adrenal glands?
Cortex and medulla.
## Footnote
These parts have different functions and produce different types of hormones.
72
What is the adrenal cortex and what does it produce?
The outer part of adrenal glands that produces three types of steroid hormones:
* Mineralocorticoids (mainly aldosterone)
* Glucocorticoids (mainly cortisol)
* Gonadocorticoids (sex hormones in small amounts)
## Footnote
The adrenal cortex is vital for various metabolic processes.
73
What is the adrenal medulla and its role?
The inner part of adrenal glands that produces protein hormones epinephrine and norepinephrine, which are synergistic and continue the fight or flight response.
## Footnote
This response lasts up to 10 times longer than the sympathetic nervous system.
74
What is the pancreas classified as?
Both an endocrine and exocrine gland.
## Footnote
This dual function is crucial for digestion and blood sugar regulation.
75
What does the exocrine function of the pancreas involve?
Secreting digestive enzymes into the duodenum.
## Footnote
This is essential for the digestive process.
76
What hormones does the endocrine function of the pancreas produce?
Insulin and glucagon.
## Footnote
These hormones play key roles in regulating blood glucose levels.
77
What are the islets of Langerhans?
Over a million small groups of cells in the pancreas containing alpha and beta cells.
## Footnote
They are responsible for hormone production within the pancreas.
78
What do alpha cells in the pancreas produce?
Glucagon, which increases blood glucose levels.
## Footnote
Glucagon plays a vital role in maintaining glucose homeostasis.
79
What do beta cells in the pancreas produce?
Insulin, which decreases blood glucose levels.
## Footnote
Insulin is crucial for the uptake of glucose by cells.
80
What are the two types of diabetes mellitus?
Type I (juvenile onset, insulin-dependent) and Type II.
## Footnote
Type I diabetes is characterized by insufficient insulin production by beta cells.
81
What characterizes Type I diabetes mellitus?
Juvenile onset and insulin dependency due to insufficient insulin production by beta cells.
## Footnote
This type of diabetes typically manifests in childhood or adolescence.
82
83
What type of diabetes is characterized by adult onset and is non-insulin dependent?
Type II diabetes
## Footnote
This type usually has enough insulin but involves a loss of receptor sites on target cells.
84
What hormone does the thymus secrete?
Thymosin
## Footnote
Thymosin is important for the development of the immune system and certain white blood cells.
85
How does the size of the thymus change from childhood to adulthood?
The thymus is large in children and shrinks in adults.
## Footnote
This change is part of normal physiological development.
86
What is the role of the thymus in the immune system?
It is where certain lymphocytes mature into T-cells.
## Footnote
T-cells are essential for adaptive immunity.
87
True or False: Type II diabetes is dependent on insulin for management.
False
## Footnote
Type II diabetes is considered non-insulin dependent.
88
Fill in the blank: The thymus secretes the hormone _______.
thymosin
