Hormones Flashcards
What type of glands are hormones secreted from?
Endocrine.
What glands are responsible for the control and levels of hormones in the body?
- Hypothalamus.
- Pituitary gland.
Name the endocrine glands?
- Pituitary.
- Hypothalamus.
- Pancreas.
- Testes/ovaries.
- Mammary glands.
- Thyroid/parathyroid.
- Adrenal cortex/medulla.
What are hormones?
Chemical messengers which control how we respond to the environment around us.
What are the key roles hormones play?
- Growth and development.
- Sleep.
- Sexual function.
- Reproduction.
- Metabolism.
- Fluid and electrolyte balance.
- Emotions and moods.
What is a target cell?
Particular cells that are able to receive and respond to the hormones message.
- They possess the appropriate hormone receptors.
How do hormones travel from the endocrine gland to the target cell?
Through the bloodstream.
Which part of the target cell do hormones connect to?
The receptor.
How do hormones differ from neuronal signalling?
- Spread slowly.
- Act throughout the body.
What are some of the changes hormones produce in the target cell?
- Permeability of the cell membrane.
- Stimulation of synthesis of proteins.
- Activation or deactivation of enzymes.
- Stimulation of cell division.
What does the change in the target cell depend on?
- The specific hormone.
- Type of target cell.
What are the 2 main groups of hormones?
1) . Steroid hormones.
2) . Protein hormones.
What is a steroid hormone?
derived from cholesterol and lipid-soluble molecules.
What are protein hormones?
Consist of amino acids.
What is a short strong of amino acids called?
Peptide hormone.
What is a single modified amino acid called?
Amine hormones.
Why are activities in the body controlled and co-ordinated?
so that homeostasis is maintained.
Which group of hormones are released when the endocrine gland is stimulated by a specific signal?
Protein hormones.
Which group of hormones are not stored in endocrine glands, and released as soon as they are made?
Steroid hormones.
Which receptors do steroid hormones interact with on the target cell?
Cytoplasmic receptors (intracellular receptors).
Which receptors do protein hormones interact with on the target cell?
Interact with the cell surface receptors (plasma membrane receptors).
What is the genomic effect?
Steroid hormones =
- bind passively to large receptor molecules in target cells.
- steroid-receptor complex binds to DNA.
- altering the expression of certain genes.
How do protein hormones interact with target cells?
- Hormone receptor complex activates chemicals (second messengers).
- These diffuse through the target cell and activate enzymes.
- Leads to activation of further enzymes in a cascade reaction.
- Activates the cell.
How do steroid hormones interact with target cells?
- Steroid hormone binds to steroid receptor in cytoplasm.
- Hormone receptor complex enters nucleus.
- Complex binds to receptor sites on chromatin.
- Activates mRNA transcription.
What embeds the protein hormone receptors?
Phospholipid bilayer of the plasma membrane.
How is hormone synthesis and release controlled?
By positive and negative feedback mechanisms.
What are the 3 ways endocrine glands, tissues or cells controlled?
1) . Chemical (ions/nutrients).
2) . Neural.
3) . Hormonal (from hypothalamus and pituitary gland).
What is the role of the hypothalamus?
- Detect internal/external stimuli.
- Link between the nervous system and endocrine system.
What is the link between the hypothalamus and pituitary gland?
Producing releasing and inhibiting hormones which regulate the action of the anterior pituitary gland.
How are hormones transported in the blood?
Attached to plasma proteins.
What do steroid hormones require in order to be transported?
A binding protein.
Which type of hormones are freely transported in the blood?
Water soluble.
Are steroid hormones water soluble or lipid soluble?
Lipid soluble.
