SEM 1 - WEEK 1 - HOMEOSTASIS PART 1 + 2

Homeostasis

Ability for the body to maintain a relatively stable internal environment. The body is able to remain in a dynamic steady state, continuously adjusting to changes that occur to adapt to the needs of the body.

Key targets of control

Blood Pressure, pH, Body Temperature, Potassium Sodium Calcium Ion Concentration Levels, Fluid Levels, Blood Glucose Levels

Positive Feedback Loop

Amplifying a change

What happens in blood Clot Positive Feedback Loop

Platelets continue attracting other platelets to form clot/scab.

Labour Contractions Positive Feedback Loop

Oxytocin amplifies contractions until childbirth is achieved.

Negative feedback loop

Opposing the initial change

Stimulus

Something that initiates a change

Receptor

Detects Changes

Input

Receptors send signals to brain through an afferent pathway

Afferent Pathway

Information arriving to brain

Output

Brain responds by sending signals through efferent pathway to the effector organs that need to respond

Response

Change from effector organs that opposes/amplifies the initial change to reach homeostasis.

Effectors

Organ or cell that acts when the brain sends signals.

Blood Glucose Regulation

After high glucose intake, beta cells in pancreas release insulin, facilitating glucose uptake into cells (muscle and liver). If blood glucose drops, alpha cells release glucagon to prompt glycogen breakdown in liver, raising blood glucose levels.

Impact of Iodine Deficiency

Iodine is crucial for T3 and T4 production. Without it, these hormones cannot be synthesized.

Low T3 and T4 levels fail to inhibit TRH, resulting in continued secretion of TRH and TSH.

Increased TSH leads to goiter, a visible sign of prolonged iodine deficiency

Role of Insulin

• Following food intake, plasma glucose rises, prompting pancreatic insulin release.

• Insulin lowers blood glucose by promoting uptake in muscle and liver tissues.

Type 1 Diabetes

1. Autoimmune destruction of beta cells in the pancreas leads to absent insulin production.

2. High blood glucose levels persist without insulin management.

Type 2 Diabetes Mellitus

1. Characterized by insulin resistance; body tissues do not effectively respond to insulin.

2. Elevated blood glucose levels post-meals as glucose removal is impaired.

Consequences of Poor Glucose Regulation

Cardiovascular diseases, Kidney Issues, Eye damage, Gum diseases