Endocrine and Cardiovascular Systems

Flashcards covering key terms and concepts related to the endocrine and cardiovascular systems, as well as some aspects of vision physiology.

Hormones

Chemical messengers produced by ductless glands that are secreted directly into the bloodstream.

Cascade Effect

A process by which a hormone activates a series of reactions in a cell despite being too large to enter.

Negative Feedback Loop

A mechanism where increased levels of a substance inhibit its further production, such as insulin regulating blood sugar.

Calcitonin

A hormone produced by the thyroid gland that helps regulate calcium levels in the blood.

Circadian Rhythm

The physical, mental, and behavioral changes that follow a daily cycle, regulated by melatonin from the pineal gland.

Nociceptors

Receptors that detect pain stimuli.

Adaptation

The process of not noticing a stimulus after a period of exposure.

Baroreceptors

Sensors that detect pressure changes within organs and blood vessels.

Plasma

The liquid component of blood, making up over 55% of its volume.

Fibrinogen

A protein essential for blood clotting.

Hematocrit

The ratio of the volume of red blood cells to the total volume of blood.

Hemocytoblast

A stem cell in the bone marrow that gives rise to all blood cells.

Hemoglobin

A protein in red blood cells that carries oxygen from the lungs to the body's tissues.

Red Blood Cell (RBC)

A biconcave disc-shaped cell without a nucleus, responsible for oxygen transport.

Monocyte

A type of white blood cell that can differentiate into macrophages.

Agglutination

The clumping of blood cells, typically due to immune response.

Left Ventricle

The chamber of the heart that pumps oxygenated blood to the entire body.

Systole

The phase of the heartbeat when the heart muscle contracts and pumps blood.

SA Node

The natural pacemaker of the heart that regulates heartbeat.

Auscultation

The act of listening to heart sounds as part of a medical examination.

Precapillary Sphincter

A band of smooth muscle that controls blood flow into capillaries.

Double Pump Heart

Describes the heart's function of pumping blood to both the lungs and the rest of the body.

Tarsal Gland

A gland that secretes oils to prevent eyelids from sticking together.

Extrinsic Eye Muscles

Muscles that control eye movement, including the superior oblique which has a trochlea.

Fovea Centralis

The part of the retina with the sharpest vision due to a high concentration of cones.

Optic Disc

The area of the eye where nerve fibers and blood vessels exit, creating a blind spot.

Ciliary Muscles

Muscles that contract to change the shape of the lens during accommodation.

Hyperopia

A vision condition also known as farsightedness.

Iris

The muscle that controls the size of the pupil.

Myopia

A vision condition also known as nearsightedness.

Strapedius and Tensor Tympani

Muscles attached to the ossicles in the middle ear, involved in sound transmission.