Biology Chapter 5: Muscle and Hormone Functions

A process where the output of a system increases the input, leading to a progressively amplified response.

Uterine contractions during childbirth are stimulated by oxytocin. The stretching of the cervix releases more oxytocin, strengthening contractions.

The smallest stable unit of an element.

A substance whose atoms are all the same type.

A substance containing two or more different types of atoms.

Atoms consist of a nucleus (protons and neutrons) surrounded by orbiting electrons.

Positively charged particle found in the atom's nucleus.

Negatively charged particle orbiting the nucleus.

Multiple layers of cells with varying shapes, deepest layers being columnar, becoming flatter towards the surface.

Stratified squamous epithelium with a tough, waterproof layer of keratin on the surface, protecting from drying.

Stratified squamous epithelium found in moist areas that need protection from drying but not needing the tough keratin layer.

Epithelial tissue with layers of pear-shaped cells, found in areas that need to stretch.

Connective tissue in the body for binding, structural support, protection, transport, and insulation.

Loose, dense, or fatty connective tissues, composed of cells like fibroblasts, macrophages, fat cells, and more.

Connective tissue cells that produce fibers.

The material between the cells in connective tissue, varying from jelly-like to rigid.

The most general connective tissue, with a semisolid matrix and many cells like fibroblasts, fat cells, and immune cells. It provides structure and elasticity to many body parts.

Connective tissue made of fat cells (adipocytes) with a supporting matrix of areolar tissue. It stores fat for energy and acts as insulation.

A type of adipose tissue that is the dominant type, storing energy and acting as insulation.

A type of adipose tissue more common in newborns, with a high capillary network. It produces heat through metabolism.

Connective tissue with more fibers and fewer cells than loose connective tissue.

A type of dense connective tissue containing closely packed collagen fibers, providing strength and support.

A type of dense connective tissue that can stretch and recoil. It contains elastic fibers.

Connective tissue with a fine matrix, reticular fibers cells, and white blood cells supporting immune function.

Specialized muscle tissue found only in the heart. It's not under conscious control and has a unique structure with intercalated discs for efficient contraction.

Specialized junctions between cardiac muscle cells. They allow for rapid and coordinated contraction of the heart muscle.

Skeletal muscles are responsible for voluntary movement. They contract and relax, producing movement of body parts or the whole body.

Smooth muscles are responsible for involuntary actions like digestion and blood vessel dilation. Their contractions are slower and more sustained than skeletal muscles.

The force of a muscle contraction depends on the number of muscle fibers contracting simultaneously.

Occurs when a muscle is repeatedly stimulated to contract. Muscle response weakens and eventually stops.

Muscles primarily obtain energy for contraction from the breakdown of carbohydrates and fats.

When oxygen supply is insufficient during intense exercise, lactic acid builds up in muscle fibers.

A moist lining found in the digestive, respiratory, and genitourinary systems. Consists of epithelial cells that produce mucus, a slimy fluid.

Specialized epithelial cells within the mucous membrane that produce and release mucus.

A double-layered membrane that secretes watery fluid. Lines cavities like the pleura, pericardium, and peritoneum.

The layer of serous membrane that lines the cavity.

The layer of serous membrane that surrounds the organ.

A membrane lining joint cavities that produces synovial fluid, a lubricant for joint movement.

Glands that release their secretions onto the epithelial surface through ducts.

Glands that release their secretions directly into the bloodstream.

Erythropoietin (EPO) stimulates the production of red blood cells (proerythrocytes), speeds up reticulocyte maturation, and ultimately increases the oxygen-carrying capacity of blood.

Hypoxia (low oxygen levels) triggers the release of erythropoietin, which then stimulates red blood cell production to increase oxygen carrying capacity in the blood.

Low levels of erythropoietin can lead to a lack of red blood cell production, even in the presence of low oxygen levels, resulting in anemia.

Red blood cells (erythrocytes) have a typical lifespan of about 120 days.

Old, damaged red blood cells are destroyed by phagocytes (specifically, macrophages) in the spleen, bone marrow, and liver.

The breakdown of heme from hemoglobin results in biliverdin, which is then converted to bilirubin, a yellow pigment.

Bilirubin, after being modified in the liver, is excreted in bile.

Antigens, inherited proteins on the surface of red blood cells, determine an individual's blood group.