Hormones Flashcards
Regulation is the process of maintaining homeostasis. What two body systems are the main participants in regulation of the body?
A. Nervous and digestive
B. Nervous and urinary
C. Nervous and endocrine
D. Endocrine and urinary
C. Nervous and endocrine
What is regulation?
- Regulation coordination of the organs of the body to help maintain homeostasis
- Stable internal environment
What is the endocrine system?
- Chemical messengers (hormones) secreted into bloodstream that alter function of other cells (target cells)
What are exocrine glands?
- Exocrine glands require a duct to transport secretions
- Typically non-hormone
- Ex. Sweat glands, pancreas (digestive juices), prostate gland
What are endocrine glands?
- Endocrine glands transport secretions directly into the bloodstream
- Typically hormone-related
- Ex. Pancreas (insulin/glucagon)
What is Paracrine signaling?
- Paracrine signaling is a cellular secretion that doesn’t require transport by the blood (affects neighboring cells only)
What are some types of hormones?
- Steroid
- Hydrophobic
- Made from cholesterol
- Ex. Testosterone and estrogen
- Protein
- Hydrophilic
- Made from amino acids
- Ex. Insulin
Which type of hormone can easily pass through a plasma membrane?
A. Hydrophobic
B. Hydrophilic
A. Hydrophobic
How does the hormone travel through the body?
- A hormone travels through the bloodstream (1)
- From source gland to target tissue
- Target tissue is determined by special receptors (2)
- Proteins in the plasma membrane (hydrophobic hormones) or cytoplasm (hydrophilic hormones)
- Specific to only ONE hormone
- Receptors act like switches to turn on or off gene expression (3,4,5)
- Causes molecular changes
- Primarily activation (or synthesis) of proteins
- Hormone/receptor complex must be deactivated when response is finished
What is usually the result of hormones?
- Hormones result (usually) is to increase the amount of activated protein/enzymes in the cell.
- Activated proteins/enzymes cause a change in the body.
A person is lacking (through genetic mutations) the receptor for a hydrophobic hormone receptor. Which of the following observations are correct?
A. There are fewer receptors in the plasma membrane of the cell
B. There is a decrease in gene expression and protein synthesis
C. There are more receptors in the cytoplasm
D. The hormone fails to enter the cell
B. There is a decrease in gene expression and protein synthesis
What endocrine glands are connected to the digestive, reproductive, and nervouse systems?
- Digestive
- Pancreas, liver
- Reproductive
- Gonads (testes, ovaries)
- Nervous
- Hypothalamus, pituitary gland, pineal gland
What do endocrine glands also consist of?
- Also consists of organs unique to the endocrine system
- Thyroid (parathyroid) and adrenal gland
- Some require CNS input, others work independent of CNS
How many glands are in the Pituitary Glands and what happens when horomones are released from these glands?
- Actually two distinct glands, closely connected with hypothalamus
- Anterior (adenohypophysis) synthesize and secrete hormones
- Posterior (neurohypophysis) store and secrete hormones
- Hormones released from pituitary typically trigger another endocrine organ to release hormones
- Additionally, the pituitary is regulated by hormones from the brain
What happens when hormones are released from the pituitary gland?
- Hormones released from pituitary typically trigger another endocrine organ to release hormones
- Additionally, the pituitary is regulated by hormones from the brain (hypothalamus)
- Three hormones are typically involved
What does the hypothalmus control?
- Hypothalmus brain tissue
- Control center for the body
- Secrete hormones that affect the anterior pituitary (adenohypophysis) gland or are stored in posterior pituitary gland
- RH = releasing hormone (see image)
- Some neurons can directly cause a gland to secrete hormones
What do hypothalamic neurons produce and what is it’s negative feedback?
- Hypothalamic neurons produces hormones
- Releasing hormone (RH) triggers release of hormones from anterior pituitary gland
- Inhibiting inhibit hormones from anterior pituitary gland
- Some are stored in posterior pituitary gland
- NEGATIVE FEEDBACK
- Resultant hormone release stops hypothalamic production of homones
- Creates a balance
Where are the Adrenal glands located and what are its two parts?
- Located on top of kidneys
- Contains two parts
- Medulla: innermost
- Cortex: outermost
What is the medulla and cortex a part of?
- Developmentally, the medulla is part of the nervous system
- Synthesizes epinephrine based on input from nervous system
- Fight or flight response
- A “normal” afferent/efferent pathway
- Developmentally, the cortex is part of the endocrine system
What is epinephrine used for when it’s released as a hormone?
- Released during “fight-or-flight response” from the adrenal gland via efferent neuron
- Has varied effects based on the target receptors
What is the Adrenal Cortex used for?
- Produces hormones when stimulated by pituitary gland
- Cortisol – “stress hormone”
- Stress = fight-or-flight
- Release extra glucose
- Keeps immune system in check (infections are a type of “stress”)
- Sex hormones – secondary source
- Help during puberty until gonads are mature
- Helps with secondary sex characteristics and estrogen production in menopausal women
What hormones are associated with the anterior pituitary gland?
Mammary Gland- PRL
Thyroid - TSH (Pituitary Thyroid Axis)
Testis, Ovary - LH, FSH (Pituitary-Gonadal axis)
Adrenal Cortex - ACTH (Pituitar-adrenal axis)
Bone, Adipose, Muscle - GH
What does the thyroid do?
- Hypothalamus secretes thyroid-releasing hormone
- Causes pituitary to secrete thyroid-stimulating
- Thyroid releases thyroid hormone (T3 and T4)
- Balances metabolic rate
- Upregulates ATP synthesis, raises heart/breathing rate, stimulates appetite, promotes alertness
What is hypothyroidism?
- Not enough hormone
- Results in fatigue, weight gain, poor muscle tone, depression
