5 Endocrine System
Objectives
- Primary and Secondary Endocrine Organs
- Hormone Actions
- Abnormal Hormone secretions
- Hormone Interactions
Interactive Activities
Critical Thinking Questions
Learning Summary
Primary Secondary Endocrine Organs
- The pituitary gland has some additional structures that should be known off.
- The anterior lobe are derived from epithelial tissues.
- The posterior lobe derived from neural tissues. The derived from epithelial tissue from neural tissue is important to when it comes to functions.
Hypothalamus/Anterior Pituitary Tropic Hormones Release
- The feedback loops help regulate multistep pathways of release several hypothalamus nd anterior pituitary tropic hormones.
Two thyroid hormones are important because these hormones regulate metabolism.
- T4: Tetraiodothyronine (thyroxin)
- T3: Triiodothyronine
Parathyroid hormone regulates calcium levels in the blood by acting on bones kidneys and intestines to increase blood calcium levels.
Hormone Actions at Target cells
The concentration of free hormone in blood depends on three factors:
1. Rate of hormone secretions (Neural vs. humeral)
It is faster secretion, more hormone in the blood, changes in target cells triggered. This is more common in adults.
2. Amount of hormone bound to plasma proteins
Example, would be stress.
3. Rate of hormone metabolism
The humoral signals (bloodbome) includes three categories:
- Hormones
- Ions
- Metabolites.
Also hormones can be secreted in response to circadian rhythms.
Primary Hypersecretion where the endocrine gland is typically the problem. Hypersecretion happens at the end of the endocrine gland. It secrets too much hormone. Example would be cortisol.
Hormone Interaction
To keep in mind that more than one hormone can affect the body function.