Chemical Signals in Animals Flashcards

Vocabulary flashcards based on the lecture notes about chemical signals in animals.

Hormone

A chemical signal secreted into the circulatory system that communicates regulatory messages within the body.

Target cells

Cells equipped to respond to a specific hormone due to the presence of receptors.

Nervous system

A system that conveys high-speed electrical signals along neurons to regulate other cells.

Endocrine system

A system that secretes hormones to coordinate slower but longer-acting responses.

Neurons

Specialized cells that convey electrical signals in the nervous system.

Paracrine signaling

Local signaling where target cells lie near the secreting cells.

Autocrine signaling

Local signaling where the target cell is also the secreting cell.

Endocrine signaling

Hormones secreted into extracellular fluids by endocrine cells, reaching targets via the bloodstream.

Synapses

Specialized junctions where neurons form connections with target cells.

Neurotransmitters

Chemicals secreted by neurons at synapses that diffuse short distances to bind to receptors on target cells.

Neuroendocrine signaling

Specialized neurosecretory cells secrete neurohormones that travel to target cells via the bloodstream.

Neurohormones

Hormones made by neurons. Unlike neurotransmitters which act locally, neurohormones enter the bloodstream.

Amines

Hormones derived from amino acids.

Polypeptides

Hormones consisting of proteins and peptides.

Steroid hormones

Lipid-soluble hormones with a specific four-ring structure.

Lipid-soluble hormones

Hormones that pass easily through cell membranes (e.g., steroid hormones).

Water-soluble hormones

Hormones that do not pass easily through cell membranes (e.g., polypeptides and amines).

Exocytosis

Secretion of water-soluble hormones from a cell.

Diffusion

The method by which lipid-soluble hormones cross cell membranes.

G protein-coupled receptor (GPCR)

A receptor on the outside of the cell that epinephrine binds to.

G protein

A protein inside the cell that is activated when epinephrine binds to GPCR.

Adenylyl cyclase

An enzyme in the membrane that converts ATP to cAMP.

cAMP

Cyclic adenosine monophosphate, a second messenger that carries signals inside the cell.

Protein Kinase A (PKA)

An enzyme that adds phosphate groups to other proteins (phosphorylation).

Adrenergic receptor

A type of GPCR that epinephrine (adrenaline) binds to.

Transcription factors

Protein-receptor complexes that regulate gene transcription in the nucleus.

Endocrine glands

Ductless organs where endocrine cells are grouped together.

Exocrine glands

Glands that have ducts and secrete substances onto body surfaces or into cavities.

Hypothalamus

The portion of the brain that contains a number of small nuclei with a variety of functions.

Pituitary gland

A gland attached to the hypothalamus, composed of the posterior and anterior pituitary.

Neurohormones

Hormones synthesized and secreted by the hypothalamus that stimulate or inhibit the secretion of pituitary hormones.

Simple hormone pathways

Hormones are released from an endocrine cell, travel through the bloodstream, and interact with specific receptors within a target cell to cause a physiological response

Simple neuroendocrine pathways

The stimulus is received by a sensory neuron, which stimulates a neurosecretory cell that releases a neurohormone into the bloodstream.

Negative feedback

A feedback loop that inhibits a response by reducing the initial stimulus.

Positive feedback

A feedback loop that reinforces a stimulus to produce an even greater response.

Posterior pituitary

Stores and secretes hormones that are made in the hypothalamus.

Anterior pituitary

Makes and releases hormones under the regulation of the hypothalamus.

Oxytocin

A neurohormone secreted by the posterior pituitary that regulates milk secretion.

Antidiuretic hormone (ADH)

A neurohormone secreted by the posterior pituitary that regulates physiology and behavior.

Prolactin (PRL)

A hormone secreted by the anterior pituitary that has a role in milk production.

Tropic hormones

Hormones that target other endocrine glands, causing them to release more hormones.

Nontropic hormones

Hormones that act directly on non-endocrine tissues.

Portal vessels

Capillary network/portal system connects the hypothalamus and anterior pituitary directly, allowing hormones to travel efficiently from one to the other

FSH (Follicle-stimulating hormone)

A tropic hormone that targets the testes or ovaries.

LH (Luteinizing hormone)

A tropic hormone that targets the testes or ovaries.

TSH (Thyroid-stimulating hormone)

A tropic hormone that targets the thyroid.

ACTH (Adrenocorticotropic hormone)

A tropic hormone that targets the adrenal cortex.

Prolactin

A nontropic hormone that acts on mammary glands to stimulate milk production.

MSH (Melanocyte-stimulating hormone)

A nontropic hormone that acts on melanocytes in the skin.

GH (Growth hormone)

A hormone with both tropic and nontropic effects, acting on tissues like bones and liver.

Thyroid hormone

A hormone that results from a hormone cascade pathway involving the hypothalamus, anterior pituitary, and thyroid gland.

TRH

Thyrotropin-releasing hormone, secreted by the hypothalamus.

Parathyroid hormone (PTH)

A hormone released by the parathyroid glands that regulates calcium levels in the blood.

Calcitonin

A hormone released by the thyroid gland that regulates calcium levels in the blood.

Adrenal glands

Glands adjacent to the kidneys, consisting of the adrenal medulla and adrenal cortex.

Adrenal medulla

The inner portion of the adrenal gland.

Adrenal cortex

The outer portion of the adrenal gland.

Corticosteroids

Steroid hormones released by the adrenal cortex in response to stress.

Glucocorticoids

Corticosteroids that influence glucose metabolism and the immune system (e.g., cortisol).

Mineralocorticoids

Corticosteroids that affect salt and water balance (e.g., aldosterone).

Catecholamines

Compounds secreted by the adrenal medulla in response to stress (e.g., epinephrine and norepinephrine).

Gonads

The testes and ovaries, which produce sex hormones.

Androgens

Male sex hormones, mainly testosterone.

Estrogens

Female sex hormones, most importantly estradiol.

Progesterone

A female sex hormone primarily involved in preparing and maintaining the uterus.

Pineal gland

A gland in the brain that secretes melatonin.

Melatonin

A hormone that helps regulate sleep-wake cycles (biorhythms).

Sexual dimorphism

The condition where males and females of the same species exhibit different physical or behavioral characteristics.

Homeostasis

The maintenance of a stable internal environment.

Synaptic signaling

Signaling that occurs when neurons secrete neurotransmitters that diffuse short distances and bind to receptors on target cells.

Hormone solubility

The ability of a hormone to dissolve in water or lipids, affecting its transport and receptor location.

Epinephrine

A hormone that mediates the body's response to short-term stress.

Releasing and inhibiting hormones

Hormones from the hypothalamus that control hormone production in the anterior pituitary.

Thyroid gland

An endocrine gland located in the neck that secretes thyroid hormones.

Gonadal sex hormones

Hormones produced by the testes and ovaries: androgens, estrogens, and progesterone.

Long-term regulation

Regulation that is long-lasting and pathway is the bloodstream.

Rapid response

Response that is very fast and pathway is the neurons.

Local regulators

Molecules that act over short distances, reaching target cells solely by diffusion.

Distant Target

It is the target of Neuroendocrine Signaling.

Nearby Target

It is the target of Synaptic Signaling.

Exocrine Glands

Secrete substances onto body surfaces or into body cavities.

Endocrine Glands

Secrete hormones into the bloodstream or surrounding fluid.

Hyper secretion

The action of excessive hormone secretion.

Hypo secretion

The action of insufficient hormone secretion.

Hormone cascade pathway

A hormone can stimulate the release of a series of other hormones, the last of which activates a non-endocrine target cell

Non-endocrine targets

Targets of Hypothalamic hormones.

Endocrine targets

Targets of Anterior pituitary hormones.

Goiter

Enlarged Thyroid Gland.

Sex hormones

Regulate formation of internal reproductive structures in human development

Mammory glands

Target of Oxytocin Hormone.

Kidney tubules

Target of ADH Hormone

Short-term

Effect Duration of Adrenal Medulla stress response.

Long-term

Effect Duration of Adrenal Cortex stress response.

Kidney

Organ Adjacent to the Adrenal Glands.

Bloodstream

Pathway of endocrine system.

Tropic Hormone

Hormone, which Trigger the Adrenal cortex.

Testosterone

Hormone, which stimulate development and maintenance of the male reproductive system

Estradiol

Hormone, which is responsible for maintenance of the female reproductive system and the development of female secondary sex characteristics

Pituitary stalk

A tubular connection to the pituitary gland.

Neurosecretory cell

A special kind of nerve cell that releases hormones instead of neurotransmitters.