Homeostasis and Feedback Mechanisms

Flashcards covering definitions, indicators, body systems, and positive and negative feedback mechanisms involved in human homeostasis.

What is homeostasis?

Homeostasis is a self-regulating process that allows an organism to maintain internal stability even when the environment changes, keeping the body working properly for survival.

What is the normal range and importance of body temperature in maintaining homeostasis?

The normal body temperature range is $36.5^\circ\text{C}\text{--}37.5^\circ\text{C}$ ($\sim 37^\circ\text{C}$), which is important for keeping enzymes functioning properly.

What is the normal fasting level of blood glucose, and why is it important?

The normal fasting blood glucose level is approximately $70\text{--}100\,\text{mg/dL}$, which is essential for providing energy to body cells.

What is the normal value and importance of blood pressure?

Normal blood pressure is approximately $120/80\,\text{mmHg}$, which ensures oxygen and nutrients reach body tissues.

Which hormones are involved in regulating blood glucose levels?

Insulin and glucagon.

What are the main organs and homeostatic role of the Nervous System?

Main organs are the brain, spinal cord, and nerves. Its role is to detect changes and harmful stimuli and send rapid signals to body organs to trigger a response.

What is the primary role of the Endocrine System in maintaining homeostasis?

It releases hormones (such as melatonin, insulin, glucagon, and oxytocin) that regulate body functions over longer periods.

What are the main organs and homeostatic role of the Circulatory System?

Main organs are the heart and blood vessels. Its role is to transport oxygen, nutrients, hormones, immune cells, and wastes throughout the body.

What is the main organ and homeostatic role of the Respiratory System?

The main organs are the lungs. Its role is to maintain proper oxygen and carbon dioxide levels in the body and help regulate blood pH.

What main organ belongs to the Urinary (Excretory) System, and what is its role in homeostasis?

The kidneys are the main organs, and they regulate water, salt balance, and waste removal from the body.

What is the main organ and homeostatic role of the Integumentary System?

The main organ is the skin, which protects the body and helps regulate temperature and heat loss through mechanisms such as sweating and goosebumps.

Which body systems interact to maintain balance when a person becomes dehydrated outdoors?

The Urinary System, Circulatory System, and Endocrine System.

Which body systems work together during a "fight-or-flight" response when being chased by a dog?

The Nervous System, Muscular System, Respiratory System, and Circulatory System.

What are the five components of a feedback mechanism?

1. Stimulus
2. Receptor
3. Control Center
4. Effector
5. Response

How is a stimulus defined in a feedback mechanism?

A stimulus is a change in an internal condition.

What is the function of a receptor in a feedback mechanism?

A receptor detects the change in the internal condition.

What is the function of the control center in a feedback mechanism?

The control center interprets information received from the receptor and sends instructions to the effector.

What is the role of an effector in a feedback mechanism?

An effector carries out the response instructed by the control center to alter internal conditions.

What is negative feedback?

Negative feedback is a process that reverses a change in order to return the body to its normal balanced state.

What is positive feedback?

Positive feedback is a process that increases or amplifies a change until a specific goal or event is completed.

How does the body restore normal blood glucose levels after a meal high in sugar?

The blood glucose level increases, causing the pancreas to release insulin, which helps body cells absorb glucose and lowers blood sugar to normal levels.

How does the body respond when blood glucose drops due to skipping a meal?

The blood glucose level decreases, causing the pancreas to release glucagon, which stimulates the release of stored glucose into the blood.

In childbirth, what are the components of the positive feedback mechanism?

Stimulus: Stretching of the cervix; Receptor: Stretch receptors in the cervix; Control Center: Hypothalamus signaling the posterior pituitary to release oxytocin; Effector: Uterine muscles; Response: Stronger contractions leading to further cervical stretching until delivery.

Why is blood clotting considered an example of positive feedback?

When blood vessels are damaged, activated platelets attract and recruit more platelets to the site, amplifying clot formation until the wound is sealed and bleeding stops.

How do the kidneys and endocrine system respond to dehydration under negative feedback?

Osmoreceptors in the hypothalamus detect increased blood concentration and trigger the posterior pituitary to release antidiuretic hormone (ADH), which causes the kidneys to reabsorb more water and produce less, more concentrated urine.