Homeostasis and Nervous System Overview

Study Notes

Homeostasis

The maintenance of a constant internal environment.
Involves controlling factors like blood glucose concentration, temperature, and body salts.
Negative Feedback Loop: A system where a change in a variable is detected and a response is triggered to counteract the change.
- Stimulus Increase: A stimulus detected as being too high triggers a response to decrease the stimulus.
- Stimulus Decrease: A stimulus detected as being too low triggers a response to increase the stimulus.

Nervous System

Responsible for rapid communication within the body.
Stimulus Detection: Receptors detect a change in the environment, generating an electrical impulse.
Sensory Neurons: Carry the electrical impulse from receptors to the central nervous system (CNS).
Synapses: Junctions between neurons that allow transmission of electrical impulses.
Central Nervous System (CNS): Includes the brain and spinal cord, where decisions are made.
- The brain makes decisions for conscious actions.
- The spinal cord handles unconscious actions (reflexes).
Motor Neurons: Carry electrical impulses from the CNS to effectors.
Effectors: Muscles or glands that produce a response.
Example: Touching a Hot Object
- Stimulus: Hot object.
- Receptors: Pain receptors in the hand.
- Sensory Neurons: Carry signal to the spinal cord.
- CNS (Spinal Cord): Processes signal and initiates a response.
- Motor Neurons: Carry a signal from the spinal cord to the muscles in the hand.
- Effectors: Muscles in the hand contract to pull the hand away.

Reflex Arc

A pathway that bypasses the brain for rapid responses to harmful stimuli.
Example: If you touch something hot, a reflex arc is triggered, causing the hand to withdraw directly without the brain processing the information.
Stimulus: Harmful stimulus.
Receptors: Detect harmful stimulus.
Sensory Neuron: Carries signal directly to the spinal cord.
Spinal Cord: Processes signal and initiates a response.
Motor Neuron: Carries signal from the spinal cord to the effector.
Effector: Muscle or gland that responds to the stimulus.

Endocrine System

Uses hormones to regulate bodily functions.
Major Glands and Hormones:
- Pituitary gland (brain): "Master gland" that controls other glands.
- Thyroid gland (neck): Produces thyroxine, regulating heart rate, metabolism, and temperature.
- Adrenal glands (above kidneys): Produce adrenaline for the "fight or flight" response.
- Pancreas (below stomach): Produces insulin and glucagon to regulate blood glucose levels.
- Testes (males): Produce testosterone, controlling puberty and sperm production.
- Ovaries (females): Produce estrogen, involved in the menstrual cycle.

Blood Glucose Maintenance

Insulin: Released when blood glucose levels are high; lowers them.
Glucagon: Released when blood glucose levels are low; increases them.
Diabetes: A condition where the body cannot regulate blood glucose properly.
- Type 1 Diabetes: Pancreas does not produce enough insulin. Treated with insulin injections.
- Type 2 Diabetes: Body becomes resistant to insulin; often due to lifestyle factors (obesity, unhealthy diet). Managed with lifestyle changes, medication, and sometimes insulin.

Menstrual Cycle

A monthly cycle of hormonal changes that prepares the female body for pregnancy.
Four Stages:
- Stage 1 (Days 1-4): Menstruation - the shedding of the uterine lining.
- Stage 2 (Days 5-14): The uterine lining rebuilds; follicles in the ovaries develop.
- Stage 3 (Day 14): Ovulation - an egg is released from the ovary.
- Stage 4 (Days 15-28): The uterine lining is maintained, preparing for implantation.
Four Key Hormones:
- FSH (Follicle Stimulating Hormone): Stimulates follicle development and estrogen production; produced by the pituitary gland.
- Estrogen: Causes the uterine lining to thicken and stimulates LH production; produced by the ovaries.
- LH (Luteinizing Hormone): Triggers ovulation; produced by the pituitary gland.
- Progesterone: Maintains the uterine lining in preparation for pregnancy; produced by the ovaries.

Description

Explore the essential concepts of homeostasis and the nervous system in this quiz. Understand the processes involved in maintaining a constant internal environment and the role of the nervous system in detecting stimuli and coordinating responses. Test your knowledge on negative feedback loops and the components of the CNS.