BIOLOGY- EXAM TESTING

What is homeostasis?

Homeostasis is defined as the constant maintenance of the body’s internal environment.

What are the two key systems involved in homeostasis?

The two key systems involved in homeostasis are the nervous system and the endocrine system.

What is the role of receptors in the stimulus-response model?

Receptors detect stimuli and send signals through neurons to the brain.

What is the difference between open and closed stimulus-response models?

In an open model, the response has no effect on the stimulus; in a closed model, the response impacts the stimulus and is monitored in a feedback loop.

Define negative feedback loop.

In negative feedback loops, if the stimulus is an increase in a variable, the response will be a decrease in that variable, and vice versa.

What is hyperthyroidism?

A condition where the thyroid gland produces too much thyroxine, leading to increased heart rate and higher body temperature.

What is hypothyroidism?

Hypothyroidism is a condition where the body produces insufficient functional thyroxine, often due to iodine deficiency, leading to symptoms like goitre.

Describe the endocrine system's function.

The endocrine system sends chemical messages throughout the body in the form of hormones produced by endocrine glands.

What are amino acid-based hormones?

Amino acid-based hormones are hydrophilic and cannot cross the plasma membrane, with receptors located on the surface of cells.

What is diffusion?

Diffusion is the passive movement of particles from an area of high concentration to an area of low concentration.

Describe facilitated diffusion.

Facilitated diffusion occurs through protein channels and can involve either channel proteins that allow polar molecules or ions to pass or carrier proteins that only let specific molecules in.

What are the three factors affecting the rate of diffusion?

The rate of diffusion is affected by concentration gradient, temperature, and particle size.

Define hormones in the context of the endocrine system.

Hormones are chemical messages produced by endocrine glands that regulate various body functions, such as growth and metabolism.

What is a control center in the stimulus-response model?

The control center processes signals from receptors and determines an appropriate response.

What are the characteristics of positive feedback loops?

In positive feedback loops, the response amplifies the original stimulus, such as during childbirth with the hormone oxytocin.

Homeostasis

The constant maintenance of a stable internal environment within an organism.

What are two primary regulatory systems of homeostasis

the nervous system and the endocrine system, which work together to maintain internal balance.

What are receptors in the stimulus-response model

Sensory structures that detect environmental changes and send signals to the control center.

Difference between open and closed stimulus-response models

In an open model, the response has no effect on the original stimulus; in a closed model, the response impacts the stimulus via a feedback loop.

what is a negative feedback loop

A control mechanism where the system's output counteracts or opposes the initial stimulus to maintain equilibrium.

What is Hyperthyroidism

A condition caused by an overactive thyroid gland producing excessive thyroxine, resulting in elevated metabolic rate, increased heart rate, and weight loss.

What is Hypothyroidism

A condition resulting from insufficient production of functional thyroxine, often due to iodine deficiency, causing a slowed metabolism and goitre.

What is the Primary function of the endocrine system

Releases hormones into the blood to control long-term processes like growth, metabolism, and development

Amino acid-based hormones

Hydrophilic chemical messengers that cannot cross the plasma membrane and instead bind to membrane-bound receptors on target cells.

Diffusion

The passive net movement of particles from an area of higher concentration to an area of lower concentration.

Positive feedback loop

A process in which the response amplifies or reinforces the original stimulus, pushing the variable further away from its initial state.

Osmosis

The passive diffusion of water molecules across a selectively permeable membrane from a region of lower solute concentration to higher solute concentration.

Active transport

The energy-requiring movement of molecules or ions across a membrane against their concentration gradient using ATP.