Vocabulary Flashcards: Nephron, Nervous System, Endocrine & Immune System

A set of vocabulary flashcards covering key terms from the nephron (kidney), nervous system, endocrine, and immune system topics in the notes.

Nephron

The functional unit of the kidney that filters blood and forms urine.

Glomerulus

A capillary tuft where filtration of blood begins into Bowman's capsule.

Bowman’s capsule

The cup-like structure surrounding the glomerulus that collects filtrate.

Proximal tubule

Renal tubule segment where major reabsorption (glucose, Na+, water) occurs.

Loop of Henle

U‑shaped tubule creating a medullary salt gradient to concentrate urine.

Descending limb

Part of the Loop of Henle permeable to water; filtrate concentrates.

Ascending limb

Part of the Loop of Henle that reabsorbs salts; water passage is limited.

Distal tubule

Tubule segment where fine-tuning of ions occurs and certain secretions take place.

Collecting duct

Tubule where water reabsorption is ADH-regulated, final urine concentration occurs.

Osmosis

Movement of water across a semipermeable membrane down its gradient.

Aquaporin

Water channel proteins in tubule membranes that facilitate water movement.

Erythropoietin

Kidney hormone that stimulates red blood cell production.

Calcitriol

Active form of vitamin D produced by the kidney that aids calcium absorption.

ADH (Antidiuretic Hormone)

Hormone that promotes water reabsorption in the collecting ducts.

Urea

A nitrogenous waste product excreted in urine.

Uric acid

Waste product from purine metabolism excreted in urine.

Creatinine

Waste product from muscle metabolism used to assess kidney function.

Filtration

Process by which plasma is filtered into Bowman's capsule from the blood.

Reabsorption

Return of water, ions, and nutrients from filtrate to blood.

Secretion

Movement of substances from blood into the tubular filtrate.

Tubular secretion

Active transport of ions and drugs from blood into filtrate.

Renal pelvis

Collecting area that drains urine into the ureter.

Urethra

Duct through which urine exits the body.

Dialysis

Treatment that removes waste when kidneys fail (hemodialysis or peritoneal dialysis).

Kidney stones

Mineral deposits that form solid stones in the kidney.

Albuminuria

Presence of albumin in urine, indicating glomerular damage.

Afferent arteriole

Blood vessel delivering blood to the glomerulus.

Efferent arteriole

Blood vessel carrying filtered blood away from the glomerulus.

Peritubular capillaries

Capillary network around tubules involved in reabsorption/secretion.

Hypothalamus

Brain region that regulates body temperature, hunger, thirst, sleep, and hormones.

Pituitary gland

Master gland; releases hormones; consists of anterior and posterior lobes.

Anterior pituitary

Glandular lobe that secretes GH, TSH, ACTH, FSH/LH, PRL, MSH.

Posterior pituitary

Lobe that stores and releases oxytocin and ADH.

Oxytocin

Hormone involved in uterine contractions and milk ejection; bonding effects.

Growth Hormone (GH)

Stimulates growth, protein synthesis, and metabolism.

TSH (Thyroid-Stimulating Hormone)

Stimulates the thyroid to release T3 and T4.

ACTH

Stimulates adrenal cortex to produce cortisol.

FSH

Governs gamete production in ovaries/testes.

LH

Triggers ovulation and stimulates sex hormone production.

Prolactin

Hormone that promotes milk production.

MSH (Melanocyte-Stimulating Hormone)

Hormone involved in melanin production in the skin.

Pineal gland

Gland that secretes melatonin to regulate sleep-wake cycles.

Grey matter

CNS region rich in neuron cell bodies; involved in processing.

White matter

CNS region rich in myelinated axons; enables fast signal transmission.

Dura mater

Outermost meningeal layer protecting the CNS.

Arachnoid mater

Middle meningeal layer with subarachnoid space containing CSF.

Pia mater

Innermost meningeal layer tightly bound to CNS.

Dorsal root

Spinal nerve root that carries sensory information to the CNS.

Ventral root

Spinal nerve root that carries motor commands from the CNS.

Lateral horn

Spinal cord region in thoracic/lumbar areas with autonomic neurons.

Spinal nerve

Mixed nerve formed by the union of dorsal and ventral roots.

Interneuron

Neuron within the CNS that connects sensory and motor pathways.

Afferent neuron

Sensory neuron that transmits signals toward the CNS.

Efferent neuron

Motor neuron that transmits signals away from the CNS to effectors.

Ganglion

Cluster of neuron cell bodies in the PNS.

Nucleus

Cluster of neuron cell bodies in the CNS.

Glial cells

Support cells that nourish, protect, and insulate neurons.

Astrocyte

Glial cell forming part of the blood–brain barrier and supporting neurons.

Oligodendrocyte

CNS glial cell that produces myelin around axons.

Schwann cell

PNS glial cell that forms myelin around peripheral axons.

Node of Ranvier

Gaps between myelin sheath segments where action potentials propagate.

Myelin sheath

Insulating layer around axons that speeds nerve impulse transmission.

Meninges

Three-layer protective coverings of the CNS (dura, arachnoid, pia).

Cerebrospinal fluid

Fluid surrounding brain and spinal cord; cushions and nourishes CNS.

Hypothalamus–pituitary axis

Neural–endocrine system coordinating hormones and homeostasis.

Thalamus

Relay station directing sensory signals to appropriate brain regions.

Thalamus

Relay station directing sensory signals to the correct brain region.

Nerve organization terms

PNS vs CNS, afferent/efferent pathways, and glial support define nervous system structure.

Antigen

Molecule recognized as foreign by immune cells; triggers an immune response.

B cells

Lymphocytes that produce antibodies and can become memory B cells.

T cells

Lymphocytes (cytotoxic and helper) crucial for adaptive immunity.

CD8+ cytotoxic T cells

T cells that kill infected or abnormal cells.

CD4+ helper T cells

T cells that activate other immune cells (B cells, cytotoxic T cells).

IL-2

Cytokine that promotes T cell proliferation and activation.

Antibodies

Proteins that neutralize pathogens via opsonization, agglutination, and complement activation.

Opsonization

Antibody-mediated marking of pathogens to enhance phagocytosis.

Agglutination

Clumping of pathogens by antibodies to facilitate clearance.

Complement system

Group of proteins that enhances immune clearance and inflammation.

Interferons

Cytokines produced by virus-infected cells to warn neighboring cells.

Fever

Elevated body temperature that can inhibit pathogen growth.

Regulatory T cells

T cells that dampen immune responses to maintain tolerance.

Memory cells

Lymphocytes that provide quicker, stronger responses on re-exposure.

Secondary immune response

Faster, stronger immune response upon a second exposure to the same antigen.