What are a pro and a con of hormones?
Pro - spread all over the place
Con - move by diffusion which is slow
Which glands secrete hormones?
Endocrine Glands
What is a Neural Signal?
Facilitated by the neurotransmitter, only between two neurons.
What are Neuroendocrine Signals?
Facilitated by Neurohormones which are hormones released by neurons.
What are Endocrine Signals?
hormones carried between cells by blood/body fluids
What are Paracrine Signals?
just look at the photo 🦧
What are Autoncrine Signals?
It’s that easy🍌
What are the three Hormone Pathways?
- The Endocrine Pathway
- Neuroendocrine Pathway
- Neuroendocrine-to-endocrine Pathway
What is the order in the Endocrine Pathway? (5)
- Stimulus -> Endocrine Cell
- Cell -> Hormone
- Hormone -> Effector Cell
- Effector Cell -> Response
- Feedback Inhibition -> Endocrine Cell
What is the order in the Neuroendocrine Pathway? (7)
- Stimulus -> Sensory Cell
- Sensory Cell -> Neurotransmitters
- Neurotransmitters -> CNS
- CNS -> Neurohormone
- Neurohormone -> Effector Cell
- Effector Cell -> Response
- Feedback Inhibition -> CNS +Sensory Cell
What is the order in the Neuroendocrine-to-endocrine pathway? (tf kinda name) (9)
- Stimulus -> Sensory Cell
- Sensory Cell -> Neurotransmitters
- Neurotransmitters -> CNS
- CNS -> Neurohormone
- Neurohormone -> Endocrine Cell
- Endocrine Cell -> Hormone
- Hormone -> Effector Cell
- Effector Cell -> Response
- Feedback Inhibition -> CNS + Sensory Cell
What is Feedback Inhibition?
What is Positive feedback?
In Feedback Inhibition, the product of a process inhibits its function.
In Contrast, Positive Feedback occurs when the product of the process stimulates (Increases) its production.
What are the 3 kinds of Hormones?
Where can u find them in the cell?
- Peptides and Polypeptides (Secretin) on Membrane Receptors
- Amino Acid Derivatives (Adrenaline) on Membrane Receptors
- Steroids (Cortisol) on Intracellular Receptors
Note There are also Thyroid Hormones which are Fatty Acid Derivatives but fuc em
What are two fundamental pathways for Hormones?
- Water-soluble (hydrophilic) hormones
(Peptides and amino acid derivatives) - Water-insoluble (lipophilic) hormones
(steroids)
Examples of Steroid Hormones?
- cortisol: stress response
- anabolic steroids - muscle growth
- sex steroids: estrogens, testosterone
- aldosterone ; Na+ resorption in kidney
Why do we need Thyroid Hormones
Thyroid Hormones are composed of Iodine, which is why the salt we buy is often fortified with iodine.
A Lack of Thyroid Hormones causes us to feel tired, sluggish and unproductive (like BISC 101)
During the Cold War, people would stock up on iodine tablets in order to prevent the accumulation of radioactive iodine that could destroy our thyroid gland
What actions do Steroid Hormones take during Gene Expression?
(Up-Regulation)
- Hormone Diffuses into Target Cell through Membrane
- Hormone Binds to Receptors in the Cytosol and moves into the nucleus
- Hormone Receptor Complex enters the nucleus and binds to DNA (hormone response element), inducing the start of transcription
- Gene Expression is turned on
Many mRNA Transcripts are produced amplifying the signal - In the cytosol, proteins are translated
What’s the difference between Up-Regulation and Down-Regulation?
Up-Regulation turns on the Gene Expression
Down-Regulations Turn off the Gene Expression
(Only in cells with the right Hormone Receptor)
What must Target Cells have to “accept” a steroid hormone?
They must have the right Intracellular Receptor.
What are Homo-Dimers?
What are Hetero-Dimers?
Homo-Dimers - two identical proteins/hormones
Hetero-Dimers - two different proteins/hormones
Describe in detail the mechanism by which steroid hormones induce a specific response in their target tissues.
Steroid hormones are water-insoluble, and hence normally need a transport protein to reach their target tissues. Because of their lipophilic nature, they can easily diffuse through the cell membrane but need an intracellular receptor that moves the hormone through the cytosol and into the nucleus.
Steroid hormones normally act by modifying gene expression; the hormone-receptor complex binds to control regions on the DNA for these genes, called hormone response elements. As long as the hormone receptor complex remains bound to its response element, the rate of transcription for the gene is turned up (upregulation) or, seldom, down (downregulation). When the hormone is broken down or otherwise removed from its receptor, the activation of the gene stops.
What hormones are present during Insect Metamorphosis?
ecdysone - triggers each molting
juvenile hormone - causes larva-larva molting
What are some Hydrophilic Hormones?
- growth hormone (GH): organ and muscle growth
- growth hormone release hormone
- antidiuretic hormone (reabsorption of water)
- insulin, glucagon (control blood sugar)
- leptin (regulation of lipid storage)
- adipokinetic hormone (insects, fat mobilization)
What does Adrenaline do?
Adrenaline “Fight or flight” hormone
* dilates pupils (vision) up
* pain sensitivity (down)
* heart rate (up)
* metabolic rate (up)
* oxygen (up)
- glucose (up)
