Endocrine system: hormones that regulate the body

Hormones and glands Hormones are chemicals that regulate: growth, development, behavior, and much more. Hormones are chemicals that regulate: growth, development, behavior, and much more. – Different hormones target different cells Hormones are produced and excreted from glands Hormones are produced and excreted from glands

common hormones Amino acid–based: usually water soluble Amino acid–based: usually water soluble – “first messenger” bind with protein receptors on outside of cell to trigger a chain reaction of events inside the cell Steroid: Usually fat soluble Steroid: Usually fat soluble – Crosses cell membrane and binds with a protein receptor inside the cytoplasm then activates DNA to produce new proteins.

Other hormones Neuropeptides: released by neurons and impact emotions Neuropeptides: released by neurons and impact emotions Prostagalandins: released when injured can change blood pressure or cause fever. Prostagalandins: released when injured can change blood pressure or cause fever.

Hypothalamus and pituitary gland Many hormones are made in the hypothalamus and stored in the pituitary gland Many hormones are made in the hypothalamus and stored in the pituitary gland Coordination between the endocrine and nervous system occur here Coordination between the endocrine and nervous system occur here Produce a range of hormones that control kidney function, blood sugar, growth, and reproductive organs Produce a range of hormones that control kidney function, blood sugar, growth, and reproductive organs

Some major glands Thyroid: maintain heart rate, blood pressure, temperature Thyroid: maintain heart rate, blood pressure, temperature Adrenal glands: stress regulation hormones & water and salt retention Adrenal glands: stress regulation hormones & water and salt retention Thymus gland: part of immune system Thymus gland: part of immune system

The body must self moderate. The body must self moderate. Two types of feedback loops: Two types of feedback loops: – Negative – Positive Negative feedback counteracts condition Negative feedback counteracts condition Positive feedback amplifies condition Positive feedback amplifies condition Negative more common. Negative more common. Feedback Loops

Negative Feedback Prevents body from moving away from a set point significantly. Prevents body from moving away from a set point significantly. Allows body to self-correct. Allows body to self-correct. Ex: controlling tempurature Ex: controlling tempurature Negative Feedback Loop

Positive Feedback Accentuates disturbance. Accentuates disturbance. Examples: Examples: – Blood clotting – Nursing a baby causes production of milk Closely regulated by negative feedback loops. Closely regulated by negative feedback loops. Positive Feedback Loop