AP Bio Unit 4 Chapter 45: Hormones and the Endocrine System

AP Bio

Hormones

Chemical signals secreted into the circulatory system.

Testosterone

A hormone influencing male elephant seal traits.

Endocrine System

System that secretes hormones for body regulation.

Nervous System

Network of neurons transmitting signals quickly.

Endocrine Signaling

Hormones reach targets via the bloodstream.

Local Signaling

Molecules travel short distances or by contact.

Long-Distance Signaling

Molecules travel long distances through the bloodstream.

Target Cells

Cells with specific receptors for certain hormones.

Neurotransmitters

Chemicals secreted by neurons across synapses.

Neurohormones

Hormones secreted by neurosecretory cells into blood.

Paracrine Signaling

Target cells are near the secreting cells.

Autocrine Signaling

Target cell is also the secreting cell.

Prostaglandins

Local regulators involved in immune and clotting functions.

Cytokines

Local regulators influencing immune responses.

Growth Factors

Local regulators promoting cell growth and division.

Nitric Oxide (NO)

Gas acting as a local regulator in blood vessels.

Homeostasis

Maintenance of stable internal conditions in the body.

Reproduction

Biological processes regulated by endocrine hormones.

Development

Growth processes influenced by hormonal signaling.

Energy Metabolism

Regulated by hormones for energy balance.

Behavior

Influenced by hormonal changes in the body.

Mating Season

Period when male seals use testosterone for territoriality.

Circulatory System

System transporting hormones throughout the body.

Nitric Oxide (NO)

A gas that relaxes smooth muscle cells.

Vasodilation

Widening of blood vessels to increase flow.

Prostaglandins

Lipids that promote inflammation and pain.

Platelet Aggregation

Clumping of platelets for blood clot formation.

Synaptic Signaling

Neurons communicate via specialized junctions called synapses.

Neurotransmitters

Chemicals secreted by neurons to transmit signals.

Neuroendocrine Signaling

Neurosecretory cells release neurohormones into blood.

Pheromones

Chemicals used for communication between animals.

Chemical Classes of Hormones

Three classes: polypeptides, steroids, and amines.

Polypeptides

Water-soluble hormones made of proteins or peptides.

Steroids

Lipid-soluble hormones derived from cholesterol.

Amines

Hormones derived from amino acids, often water-soluble.

Water-Soluble Hormones

Cannot pass cell membranes; bind to surface receptors.

Lipid-Soluble Hormones

Easily pass through membranes; bind to intracellular receptors.

Exocytosis

Process for water-soluble hormones to be secreted.

Signal Transduction

Conversion of a chemical signal to an intracellular response.

Cortisol

Hormone that regulates stress responses in the body.

G Protein-Coupled Receptors

Receptors that initiate signaling cascades upon hormone binding.

cAMP

Second messenger involved in signaling pathways.

Gene Expression

Process altered by lipid-soluble hormones in target cells.

Hormone-Receptor Complex

Formed when a hormone binds to its receptor.

Transcriptional Regulator

Complex that influences gene transcription in the nucleus.

Vitellogenin Gene

Gene activated by estradiol for egg yolk production.

Thyroxine

A lipid-soluble hormone with nuclear receptors.

Hormone Receptor

Binds hormones and stimulates gene transcription.

Epinephrine

Hormone triggering 'fight-or-flight' response.

Signal Transduction Pathway

Process by which a signal is transmitted.

Endocrine Glands

Ductless organs secreting hormones into fluid.

Exocrine Glands

Glands with ducts secreting onto surfaces.

Simple Endocrine Pathway

Direct hormone response to a stimulus.

Neuroendocrine Pathway

Stimulus received by neuron, triggering neurohormone release.

Negative Feedback Loop

Response reduces initial stimulus to maintain balance.

Positive Feedback Loop

Response amplifies stimulus for greater effect.

Insulin

Hormone decreasing blood glucose levels.

Glucagon

Hormone increasing blood glucose levels.

Pancreatic Islets

Clusters of endocrine cells in the pancreas.

Secretin

Hormone raising pH in the duodenum.

Oxytocin

Hormone stimulating milk release during suckling.

Glycogen Breakdown

Process releasing glucose from liver cells.

Pituitary Gland

Major endocrine gland controlling other glands.

Thyroid Gland

Regulates metabolism and energy levels.

Adrenal Glands

Secrete hormones for stress response.

Thymus

Organ involved in immune system development.

Feedback Regulation

Mechanism controlling hormone levels in the body.

Homeostasis

Maintaining stable internal conditions in organisms.

Ductless Organs

Organs that release hormones directly into blood.

Hormonal Antagonism

Opposing effects of hormones on target cells.

Insulin

Hormone that lowers blood glucose levels.

Beta cells

Pancreatic cells that release insulin.

Glucose uptake

Process of cells absorbing glucose.

Glycogen

Stored form of glucose in the liver.

Glucagon

Hormone that raises blood glucose levels.

Alpha cells

Pancreatic cells that release glucagon.

Homeostasis

Stable internal environment in the body.

Blood glucose level

Normal range is 70-110 mg/mL.

Type 1 diabetes

Autoimmune destruction of insulin-producing cells.

Type 2 diabetes

Insulin resistance or deficiency in target cells.

Neuroendocrine signaling

Coordination between nervous and endocrine systems.

Metamorphosis

Transformation process in insect development.

PTTH

Hormone that triggers molting in insects.

Ecdysteroid

Hormone that promotes molting and metamorphosis.

Juvenile hormone (JH)

Hormone that regulates insect development stages.

Hypothalamus

Brain region controlling endocrine functions.

Pituitary gland

Master gland regulating other endocrine glands.

Posterior pituitary

Stores and releases hormones from hypothalamus.

Antidiuretic hormone (ADH)

Regulates water balance and urine concentration.

Oxytocin

Stimulates uterine contractions and milk secretion.

Anterior pituitary

Produces hormones regulating various body functions.

Prolactin (PRL)

Hormone involved in milk production.

Releasing hormones

Hormones from hypothalamus stimulating anterior pituitary.

Tropic hormones

Hormones from anterior pituitary that stimulate other glands.

Thyroid hormone

Regulates metabolism and many bodily functions.

Thyrotropin-releasing hormone (TRH)

Stimulates anterior pituitary to release TSH.

Thyroid-stimulating hormone (TSH)

Stimulates thyroid gland to release thyroid hormones.

Goiter

Enlargement of thyroid due to insufficient iodine.

Triiodothyronin (T3)

Thyroid hormone with three iodine atoms.

Thyroxine (T4)

Thyroid hormone with four iodine atoms.