Biology Chapter on Tumors and Nervous System

Malignant tumors that invade and destroy surrounding tissues but do not spread to distant organs.

The control center of the nervous system, including the brain and spinal cord.

The network of nerves that extends throughout the body, connecting the CNS to the rest of the body.

The part of the PNS controlling voluntary movements of skeletal muscles

The part of the PNS controlling involuntary actions, such as heart rate, digestion, and breathing.

Chemical messengers that transmit signals across synapses between neurons.

The junction between two neurons, where signals are transmitted.

A series of neurons that mediates a reflex action, typically involving sensory input, integration, and motor output.

Genes that control a cell's programmed death (apoptosis).

These genes suppress uncontrolled cell growth and division.

A gene that normally acts as a 'break' on cell growth, preventing the development of cancer. Mutations in this gene can lead to cancer.

A gene that normally prevents cell growth and division. Mutations in this gene are linked to specific cancers, including childhood eye cancer.

Genes that repair DNA damage that might happen during cell replication and exposure to environmental factors.

The ability of cancer cells to disregard signals that would normally inhibit their growth.

The ability of cancer cells to grow and divide without external stimulation.

These are eight fundamental changes in cell physiology that are characteristic of cancer.

Drugs that inhibit the production of prostaglandins (PGs) by blocking the release of arachidonic acid from cell membranes. They work by inhibiting phospholipase A2 (PLA2).

Drugs that inhibit the production of prostaglandins (PGs) by directly inhibiting their synthesis through the COX enzyme system. They are also known as COX inhibitors.

Enzyme responsible for converting arachidonic acid into prostaglandins (PGs).

Two forms of the COX enzyme: COX-1 and COX-2. While both are involved in prostaglandin synthesis, they have different roles in the body.

NSAIDs that inhibit both COX-1 and COX-2 enzymes. They can have a broader effect on prostaglandin production, leading to both beneficial and adverse effects.

NSAIDs that selectively inhibit COX-2. This approach aims to reduce side effects by minimizing the impact on COX-1.

Long-term use of NSAIDs, especially non-selective ones, can lead to various side effects, including gastrointestinal problems, cardiovascular issues, and kidney damage.

Despite their effectiveness in acute inflammation, NSAIDs are not a cure for the underlying cause of the disease.

A reflex with a single synapse between the afferent (sensory) and efferent (motor) neurons.

A reflex involving one or more interneurons between the afferent and efferent neurons.

A reflex triggered by stretching a skeletal muscle, resulting in contraction of the stretched muscle. The knee-jerk reflex is a classic example.

A reflex that withdraws a body part from a painful stimulus. It involves flexor muscle contraction and extensor muscle inhibition.

A reflex that controls involuntary actions such as bladder emptying and digestion. It involves afferent and efferent pathways within the autonomic nervous system.

A reflex that occurs in the bladder when stretch receptors are activated by bladder wall stretching. It initiates muscle contractions for urination.

A wave of muscle contractions that moves food along the digestive tract. It is initiated by stretching of the gut wall.

Smooth muscle cells are connected by gap junctions, allowing rapid transmission of nerve impulses.

Smooth muscles contract in response to hormones like oxytocin, which triggers uterine muscle contraction.

Some smooth muscles produce substances, like collagen and elastin, that contribute to the extracellular matrix.

Smooth muscle cells can divide, increasing muscle mass. This is prominent during pregnancy.

Smooth muscle can repair itself by forming new cells through mitosis or differentiation of pericytes.

The covering of epithelial cells that lines surfaces and cavities in the body.

The study of epithelial tissue, including its structure, function, and relevance in the human body.

The unique structural features of different types of epithelium are related to their specific functions.

The process by which tumors induce the growth of new blood vessels to supply them with nutrients and remove waste. This is essential for tumor growth beyond a small size.

Tumor vessels are different from normal blood vessels, often dilated and leaky, with slower and abnormal blood flow.

This process involves tumor cells breaking away from the primary tumor, degrading the surrounding tissue, and spreading to distant sites.

Tumor cells can break away from each other due to a decrease in cadherins, which are adhesion molecules that normally hold cells together.

Tumor cells produce enzymes called proteases that break down the extracellular matrix, allowing them to invade surrounding tissues.

Tumor cells must attach to the surrounding tissue using adhesion molecules that interact with the ECM.

Tumor cells exhibit increased movement and migration, enabling them to spread. This can be driven by chemotactic factors, degraded ECM components, and growth factors.

Tumor cells can travel through the bloodstream and lymphatic system, eventually lodging in a new location where they may start growing. This process is influenced by factors like the primary tumor's location, specific receptors on the tumor cells, and the microenvironment of the new site.