University:
Sam Houston State University
Course:
BIOL 1406 | General Biology I
Academic year:

2023
Views:

108

Pages:

6
Author:

StellarStrategist

The Endocrine System Anatomy and Physiology The Endocrine System The Endocrine System • – – A group of ductless glands that release hormones into the circulatory system – • • – Greatly effects growth and development Animal must have proper levels of all nutrients, especially minerals, for proper functioning. These hormones produce gradual change, instead of immediate change like the nervous system. Football player: nervous system directs him to run and catch pass, endocrine system causes rate of growth. Function is to work with nervous system in the internal control of the body. This is accomplished by specific hormones secreted by specific glands. 2 Hormones • – – – Chemical substances that travel through the bloodstream and effect a gland or organ • • • • • They regulate many of the activities in the body by acting as messengers, relaying information. Growth Reproduction Milk Production Breathing Rate Only needed in very minute amounts 1/100,000,000 gram of oxytocin hormone will stimulate the almost immediate letdown on milk in female animals. They are always in the blood in varying amounts. 3 Glands • A cell or group of cells (tissue) that secretes fluids. – Hypothalamus is the portion of the brain that controls the pituitary gland, or master endocrine gland. • Also synthesizes antidiuretic hormone and oxytocin for uterus contraction during birth. 4 – Principle Endocrine Glands • • – • • • – • • – • • Pituitary Gland: Master endocrine gland, linked to hypothalamus with nerves and vessels Creates amino acid hormones Controls adrenal gland, thyroid gland, ovaries, testis, mammary glands, stores hypothalamus hormones and secretes growth hormone. Thyroid gland Creates amino acid hormones Secretes thyroxin to stimulate growth and metabolism and secretes calcitonin Parathyroid gland secretes amino acid hormones and parathyroid hormone Adrenal gland Adrenal Medulla creates amino acid hormones and secretes epinephrine and norepinephrine Adrenal Cortex creates steroid hormones and secretes glucocorticoid and aldosterone Reproductive glands Ovary: secretes steroid hormones – female sex hormones Testis: secretes steroid hormones – male sex hormones 5 Adrenaline – Inner portion of adrenal gland secretes epinephrine (adrenaline) and norepinephrine. • Fight or flight response – Hypothalamus relays impulses to nervous system, which stimulates adrenal glands to increase output of epinephrine (adrenaline) and norepinephrine. • These hormones increase heart rate, blood pressure, respiration rate • Increase efficiency of muscle contractions and blood sugar levels • Usually known as an “adrenaline rush.” Body prepares to face or flee the situation. 6