80 Questions
What is the primary function of inhibitory G proteins in hormone signaling?
To decrease the activity of intracellular enzymes
What is the role of JAK2 in the leptin receptor signaling pathway?
To phosphorylate and activate STAT proteins
What is the characteristic of hormones that bind with protein receptors inside the cell?
They are lipid soluble
What is the outcome of the activated hormone-receptor complex binding with the hormone response element?
Activation or repression of transcription of specific genes
What is the function of the homodimeric leptin receptor?
To bind with leptin and activate intracellular signaling pathways
What is the role of STAT proteins in the leptin receptor signaling pathway?
To activate the transcription of target genes
What is the outcome of hormone binding to stimulatory G proteins?
Increase in the activity of intracellular enzymes
What is the location of the hormone response element in the cell?
In the nucleus
What is the primary effect of growth hormone on glucose utilization in the body?
Decreased glucose utilization
How does growth hormone enhance protein deposition in tissues?
By enhancing amino acid transport through cell membranes
What is the effect of growth hormone on fatty acid mobilization and utilization?
Increased fatty acid mobilization and utilization
What is the effect of growth hormone on protein synthesis in most cells of the body?
Increased protein synthesis
What is the role of growth hormone in conserving carbohydrates in the body?
By decreasing glucose utilization
How does growth hormone affect the concentration of amino acids in cells?
Increases amino acid concentration
What is the mechanism by which growth hormone increases protein synthesis in cells?
By enhancing RNA translation in the cytoplasm
What is the long-term effect of growth hormone on RNA formation in the nucleus?
Increased RNA formation
What is the primary function of the suprachiasmatic nucleus (SCN) in the hypothalamus?
Serving as a master clock that controls rhythmic patterns of biological clocks
What is the primary mechanism by which the body adapts to changes in stresses and demands over the course of a day?
Cyclical changes in hormone concentrations
What percentage of steroid or thyroid hormones in the plasma typically exist free in solution?
Less than 10%
What type of hormones are dissolved in the plasma and transported from their sites of synthesis to target tissues?
Water-soluble hormones such as peptides and catecholamines
What is the primary function of the circadian clock in the context of hormone secretion?
Driving oscillations of endocrine signaling
What is the primary role of the rhythmic changes in female sex hormones that occur with an average 28-day cycle?
Essential for reproduction
What is the primary mechanism by which steroid and thyroid hormones are transported in the bloodstream?
Bound to plasma proteins
What is the primary function of the feedback signals to the endocrine gland?
Slowing further synthesis and secretion of the hormone
What is the outcome of GH's ability to mobilize large quantities of free fatty acids from adipose tissue?
Supplying most of the energy for the body's cells
What is the effect of GH on amino acid uptake and protein synthesis by cells?
It enhances almost all facets of amino acid uptake and protein synthesis
What is the outcome of GH's ability to promote fat utilization for energy?
Increased lean body mass
What is the time frame for GH to enhance protein synthesis?
Minutes
What is the outcome of excessive GH on fat mobilization from adipose tissue?
Formation of large quantities of acetoacetic acid
What is the effect of GH on glucose uptake in tissues such as skeletal muscle and fat?
Decreased glucose uptake
What is the effect of GH on insulin secretion?
Increased insulin secretion
What is the outcome of excessive GH on the liver?
Frequent fatty liver
What is the primary cause of excess growth hormone production in severe protein malnutrition?
Protein deficiency
What is the effect of protein treatment on plasma growth hormone concentration in severe protein deficiency?
It decreases the growth hormone concentration
What is the function of somatostatin in regulating growth hormone secretion?
It inhibits growth hormone secretion
What is the composition of growth hormone-releasing hormone (GHRH)?
44 amino acids
What is the effect of carbohydrate treatment on growth hormone concentration in severe protein deficiency?
It has no effect on the growth hormone concentration
What is the route of transportation of GHRH and somatostatin to the anterior pituitary gland?
Hypothalamic-hypophysial portal vessels
What is the composition of somatostatin?
14 amino acids
What is the effect of protein deficiency on growth hormone concentration?
It increases the growth hormone concentration
What is the primary function of the suprachiasmatic nucleus (SCN) in the hypothalamus?
Controlling rhythmic patterns of biological clocks
What is the primary mechanism by which the body adapts to changes in stresses and demands over the course of a day?
Changes in hormone secretion driven by neural pathways
What percentage of steroid or thyroid hormones in the plasma typically exist free in solution?
Less than 10%
What type of hormones are dissolved in the plasma and transported from their sites of synthesis to target tissues?
Peptides and catecholamines
What is the primary function of the circadian clock in the context of hormone secretion?
Controlling the rhythmic patterns of hormone secretion
What is the primary role of the rhythmic changes in female sex hormones that occur with an average 28-day cycle?
Regulating the menstrual cycle
What is the primary mechanism by which steroid and thyroid hormones are transported in the bloodstream?
Bound to plasma proteins
What is the primary function of the feedback signals to the endocrine gland?
Slowing further synthesis and secretion of the hormone
What is the primary reason why even small concentrations of a hormone can have a large effect?
Because the hormone initiates a cascade of reactions in the cell
What is the typical location of receptors for steroid hormones?
In the cell cytoplasm
What is the primary function of hormone receptors?
To initiate hormonal effects
What is the outcome of the formation of a hormone-receptor complex?
The function of the receptor is altered
What determines the type of hormone that will act on a particular tissue?
The specificity of the receptor for a particular hormone
What is the typical location of receptors for thyroid hormones?
In the cell nucleus
What is the primary reason why hormone receptors are specific for a particular hormone?
Because the receptor is highly specific for a particular hormone
What is the outcome of the activation of a hormone receptor?
The target tissue is stimulated
What is the primary characteristic of steroid hormones in the body?
They are synthesized from cholesterol and are not stored.
What is the common feature of hormones secreted by the adrenal cortex, ovaries, testes, and placenta?
They are all steroid hormones.
What is the smallest size of peptides that can be considered hormones?
Three amino acids.
What is the location where polypeptide and protein hormones are synthesized in endocrine cells?
Rough endoplasmic reticulum.
What is the term for polypeptides with fewer than 100 amino acids?
Peptides.
What is the process by which preprohormones are converted into smaller prohormones?
Cleavage.
What is the anatomical location of the parathyroid glands?
Behind the thyroid gland.
What is the term for hormones that are synthesized from the amino acid tyrosine?
Derivatives of tyrosine.
What is the primary function of stimulatory G proteins in hormone signaling?
To increase the activity of intracellular enzymes
What is the mechanism by which lipid-soluble hormones interact with receptors inside the cell?
They cross the cell membrane and interact with receptors in the cytoplasm or nucleus
What is the outcome of the activated hormone-receptor complex binding with the hormone response element?
Activation of transcription of target genes
What is the function of janus kinase 2 (JAK2) in the leptin receptor signaling pathway?
To phosphorylate and activate STAT proteins
What is the characteristic of hormones that bind with protein receptors inside the cell?
They are lipid-soluble
What is the outcome of the leptin receptor signaling pathway?
Activation of transcription of target genes
What is the function of the hormone response element in the cell?
To bind with the activated hormone-receptor complex
What is the role of G proteins in hormone signaling?
To couple hormone receptors to stimulatory or inhibitory signaling pathways
What is the primary function of hypothalamic releasing and inhibitory hormones?
To control secretion of the anterior pituitary hormones
What is the structure of thyrotropin-releasing hormone (TRH)?
A single chain of 3 amino acids
What is the primary action of corticotropin-releasing hormone (CRH)?
Stimulates secretion of ACTH by corticotropes
What is the function of prolactin-inhibiting hormone (PIH)?
Inhibits synthesis and secretion of prolactin by lactotropes
What is the composition of growth hormone-releasing hormone (GHRH)?
A single chain of 44 amino acids
What is the function of growth hormone inhibitory hormone (somatostatin)?
Inhibits secretion of growth hormone by somatotropes
How do hypothalamic releasing and inhibitory hormones reach the anterior pituitary gland?
Through the hypothalamic-hypophysial portal system
What is the structure of gonadotropin-releasing hormone (GnRH)?
A single chain of 10 amino acids
This quiz covers the relationship between hormone secretion and circadian clocks, including the role of the suprachiasmatic nucleus and rhythmic patterns of biological clocks.
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