We defined an endocrine signal as a chemical message that travels through the blood. Here, we want to talk about the endocrine system as all the things that release and respond to those chemical messengers. So we're going to do that first by sort of breaking down that signal a little bit more. We're going to talk about what releases the signal, how it is received. We're going to look at the different glands that release those chemical messengers, and then we're going to talk about the types of things in the body that the endocrine system is largely responsible for regulating. So we're going to do that all by talking about the components of the endocrine system, and right now, though, we just want to give this sort of general picture. There's a lot more details that we're going to go over, but we want to give this general picture, so when you get those specific pieces, you understand a little bit better how they fit together. We're going to start with the glands, and the glands are going to be structures that are specialized for secreting substances. And you might remember we have exocrine glands, and we have endocrine glands. Exocrine glands are responsible for secreting substances onto a body surface, things like sweat. And then we have endocrine glands, and endocrine glands release hormones, those chemical messengers, specifically into the blood. Alright. Well, we have our list of endocrine glands here. Let's so let's go through them. It is very likely that you're going to be responsible for the names, the locations, and the hormones produced by these endocrine glands. Now right now, again, we're just giving an overview. There's a lot more specifics we're going to get into, but we want to give you a general picture so when we get to those specifics, you understand how it all fits together. So we'll start with the hypothalamus. The hypothalamus is actually a region of the brain. So it's part of the nervous system, and it's right sort of up there in the middle of the brain, and it largely regulates homeostasis. Well, the endocrine system is responsible for controlling many homeostatic variables. So this is how the nervous system and the endocrine system talk to each other. We go down. We have the pineal gland. And here in the pineal gland, we have a small gland sort tucked in the back of the brain. That's responsible for regulating your sleep and wake or your circadian rhythms. We have the pituitary gland. The pituitary gland sort of right here, right under the hypothalamus. And when we say that the nervous system and the endocrine system talk to each other, it's between that hypothalamus and the pituitary gland. The pituitary gland makes a whole bunch of hormones, and many of those hormones go out and tell other endocrine glands what hormones they should release. As we go down, we have the thyroid gland and the parathyroid gland or glands, and that's right here. The thyroid gland is a larger gland largely responsible for regulating the body's metabolism, and the parathyroid glands are 4 very small glands on the thyroid gland that regulate the body's calcium levels. We go down. We have the thymus. The thymus is this gland here in the chest. The thymus is very active in childhood, and it gets less and less active as you age. We have the adrenal gland, or adrenal glands. These are two glands sitting right there on top of the kidneys. They're largely responsible for responding to stress. We have the pancreas, this sort of yellow gland here tucked in by the stomach. The pancreas is actually part of the digestive system and the endocrine system. It releases digestive enzymes into the intestines, but it also releases hormones that regulate blood glucose levels. And then finally, we have the gonads. In females, that's the ovaries and in males, the testes. You can see those drawn here. We have the female reproductive system on the left with the ovaries, and we have a testis of the male reproductive system there on the right. These are going to be responsible for releasing the sex hormones. Alright. So that's that list of glands, but an important thing to note is that there are actually many other organs that also release hormones. What makes something part of the endocrine system is that it releases a hormone, a chemical messenger that travels through the blood. Now that's really the main job of these things, but other things in the body do it as well. For example, fat cells release hormones. These other things we usually don't list as a major component of the endocrine system, well, because a lot of things do it, and their main job is part of some other system. Alright. As we go down, the things that get released, that's the hormone. And we've defined this before, but let's do it again. Hormones are going to be these chemical messengers that circulate in blood. And the way I think of a hormone is that the hormone gets sent out to sort of just give a general message. Hey, this is the state of the body, or this is something generally that's happening in the body right now. It gets put in the blood, and that's because the blood goes basically everywhere. So now the entire body has this sort of update. Hey, this is something that's happening right now. Now what responds to that? What responds is going to be the target cells. The target cells are the cells with a specific receptor. So the hormone goes basically everywhere, but not everything responds. Depending on the message, some things may not have to do anything, so they don't even have the receptor. Some things will respond one way, other cells will respond a different way. The hormone is a general message saying, hey, this is what's happening right now. The target cells with the receptors will respond differently depending on what their job is in responding to that signal. Alright. So what types of things are we talking about regulating here? Well, here we've broken them up into 5 sort of generalized groups. Now this isn't an official grouping, but this is just sort of an easy way that I like to think about it. So we're going to say here the hormones can help control a variety of bodily functions. We have growth and development, and we have an image here of a baby looking like growing up to be this person here who's like an adolescent. You can imagine the amount of changes, anatomically and physiologically, that happened going from a baby to an adolescent. That takes a lot of coordination. The endocrine system is going to be largely responsible for that. Reproduction. Well, as this image, we have a woman here who looks fairly pregnant there. Reproduction. The production of gametes. Hormone cycling as part of reproduction. And then also in pregnancy, regulating those body changes so that the body is able to support a growing fetus. We have electrolyte balance. And for this, we have a gentleman here who looks kind of thirsty. Electrolyte balance. The endocrine system is responsible for telling the kidneys how much urine to make, so that we have the right amount of volume of water in our blood. We have metabolism, and we have a woman here who looks pretty happy eating a piece of pizza. How our body processes different food molecules, that's going to be responding to signals from the endocrine system. And then we have active body defenses, and we have a gentleman here running away from a rattlesnake, it looks like. So you've probably heard of a fight or flight response. That's largely controlled by the hormone adrenaline. But we have other hormones that control other types of stress responses as well. Okay. So, again, this is our sort of general picture of the endocrine system, the types of things it does. We're going to get into a lot more details coming up. I'm looking forward to it. I hope you are too.
Table of contents
- 1. Introduction to Anatomy & Physiology5h 40m
- What is Anatomy & Physiology?20m
- Levels of Organization13m
- Variation in Anatomy & Physiology12m
- Introduction to Organ Systems27m
- Homeostasis9m
- Feedback Loops11m
- Feedback Loops: Negative Feedback19m
- Feedback Loops: Positive Feedback11m
- Anatomical Position7m
- Introduction to Directional Terms3m
- Directional Terms: Up and Down9m
- Directional Terms: Front and Back6m
- Directional Terms: Body Sides12m
- Directional Terms: Limbs6m
- Directional Terms: Depth Within the Body4m
- Introduction to Anatomical Terms for Body Regions3m
- Anatomical Terms for the Head and Neck8m
- Anatomical Terms for the Front of the Trunk8m
- Anatomical Terms for the Back9m
- Anatomical Terms for the Arm and Hand9m
- Anatomical Terms for the Leg and Foot15m
- Review- Using Anatomical Terms and Directions12m
- Abdominopelvic Quadrants and Regions19m
- Anatomical Planes & Sections17m
- Organization of the Body: Body Cavities13m
- Organization of the Body: Serous Membranes14m
- Organization of the Body: Serous Membrane Locations8m
- Organization of the Body: Thoracic Cavity8m
- Organization of the Body: Abdominopelvic Cavity12m
- 2. Cell Chemistry & Cell Components12h 37m
- Atoms- Smallest Unit of Matter57m
- Isotopes39m
- Introduction to Chemical Bonding19m
- Covalent Bonds40m
- Noncovalent Bonds5m
- Ionic Bonding37m
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- Introduction to Water7m
- Properties of Water- Cohesion and Adhesion7m
- Properties of Water- Density8m
- Properties of Water- Thermal14m
- Properties of Water- The Universal Solvent17m
- Acids and Bases12m
- pH Scale21m
- Carbon8m
- Functional Groups9m
- Introduction to Biomolecules2m
- Monomers & Polymers11m
- Carbohydrates23m
- Proteins25m
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- Lipids28m
- Microscopes10m
- Prokaryotic & Eukaryotic Cells26m
- Introduction to Eukaryotic Organelles16m
- Endomembrane System: Protein Secretion34m
- Endomembrane System: Digestive Organelles15m
- Mitochondria & Chloroplasts21m
- Endosymbiotic Theory10m
- Introduction to the Cytoskeleton10m
- Cell Junctions8m
- Biological Membranes10m
- Types of Membrane Proteins7m
- Concentration Gradients and Diffusion9m
- Introduction to Membrane Transport14m
- Passive vs. Active Transport13m
- Osmosis33m
- Simple and Facilitated Diffusion17m
- Active Transport30m
- Endocytosis and Exocytosis15m
- 3. Energy & Cell Processes10h 7m
- Introduction to Energy15m
- Laws of Thermodynamics15m
- Chemical Reactions9m
- ATP20m
- Enzymes14m
- Enzyme Activation Energy9m
- Enzyme Binding Factors9m
- Enzyme Inhibition10m
- Introduction to Metabolism8m
- Redox Reactions15m
- Introduction to Cellular Respiration22m
- Types of Phosphorylation11m
- Glycolysis19m
- Pyruvate Oxidation8m
- Krebs Cycle16m
- Electron Transport Chain14m
- Chemiosmosis7m
- Review of Aerobic Cellular Respiration19m
- Fermentation & Anaerobic Respiration23m
- Introduction to Cell Division22m
- Organization of DNA in the Cell17m
- Introduction to the Cell Cycle7m
- Interphase18m
- Phases of Mitosis48m
- Cytokinesis16m
- Cell Cycle Regulation18m
- Review of the Cell Cycle7m
- Cancer13m
- Introduction to DNA Replication22m
- DNA Repair7m
- Central Dogma7m
- Introduction to Transcription20m
- Steps of Transcription19m
- Genetic Code25m
- Introduction to Translation30m
- Steps of Translation23m
- Post-Translational Modification6m
- 4. Tissues & Histology10h 3m
- Introduction to Tissues & Histology16m
- Introduction to Epithelial Tissue24m
- Characteristics of Epithelial Tissue37m
- Structural Naming of Epithelial Tissue19m
- Simple Epithelial Tissues1h 2m
- Stratified Epithelial Tissues55m
- Identifying Types of Epithelial Tissue32m
- Glandular Epithelial Tissue26m
- Introduction to Connective Tissue36m
- Classes of Connective Tissue8m
- Introduction to Connective Tissue Proper40m
- Connective Tissue Proper: Loose Connective Tissue56m
- Connective Tissue Proper: Dense Connective Tissue49m
- Specialized Connective Tissue: Cartilage44m
- Specialized Connective Tissue: Bone12m
- Specialized Connective Tissue: Blood9m
- Introduction to Muscle Tissue7m
- Types of Muscle Tissue45m
- Introduction to Nervous Tissue8m
- Nervous Tissue: The Neuron8m
- 5. Integumentary System2h 20m
- 6. Bones & Skeletal Tissue2h 16m
- An Introduction to Bone and Skeletal Tissue18m
- Gross Anatomy of Bone: Compact and Spongy Bone7m
- Gross Anatomy of Bone: Periosteum and Endosteum11m
- Gross Anatomy of Bone: Bone Marrow8m
- Gross Anatomy of Bone: Short, Flat, and Irregular Bones5m
- Gross Anatomy of Bones - Structure of a Long Bone23m
- Microscopic Anatomy of Bones - Bone Matrix9m
- Microscopic Anatomy of Bones - Bone Cells25m
- Microscopic Anatomy of Bones - The Osteon17m
- Microscopic Anatomy of Bones - Trabeculae9m
- 7. The Skeletal System2h 35m
- 8. Joints2h 17m
- 9. Muscle Tissue2h 33m
- 10. Muscles1h 11m
- 11. Nervous Tissue and Nervous System1h 35m
- 12. The Central Nervous System1h 6m
- 13. The Peripheral Nervous System1h 26m
- Introduction to the Peripheral Nervous System5m
- Organization of Sensory Pathways16m
- Introduction to Sensory Receptors5m
- Sensory Receptor Classification by Modality6m
- Sensory Receptor Classification by Location8m
- Proprioceptors7m
- Adaptation of Sensory Receptors8m
- Introduction to Reflex Arcs13m
- Reflex Arcs15m
- 14. The Autonomic Nervous System1h 38m
- 15. The Special Senses2h 41m
- 16. The Endocrine System2h 48m
- 17. The Blood1h 22m
- 18. The Heart1h 42m
- 19. The Blood Vessels3h 35m
- 20. The Lymphatic System3h 16m
- 21. The Immune System14h 37m
- Introduction to the Immune System10m
- Introduction to Innate Immunity17m
- Introduction to First-Line Defenses5m
- Physical Barriers in First-Line Defenses: Skin13m
- Physical Barriers in First-Line Defenses: Mucous Membrane9m
- First-Line Defenses: Chemical Barriers24m
- First-Line Defenses: Normal Microbiota7m
- Introduction to Cells of the Immune System15m
- Cells of the Immune System: Granulocytes28m
- Cells of the Immune System: Agranulocytes26m
- Introduction to Cell Communication5m
- Cell Communication: Surface Receptors & Adhesion Molecules16m
- Cell Communication: Cytokines27m
- Pattern Recognition Receptors (PRRs)48m
- Introduction to the Complement System24m
- Activation Pathways of the Complement System23m
- Effects of the Complement System23m
- Review of the Complement System13m
- Phagocytosis17m
- Introduction to Inflammation18m
- Steps of the Inflammatory Response28m
- Fever8m
- Interferon Response25m
- Review Map of Innate Immunity
- Introduction to Adaptive Immunity32m
- Antigens12m
- Introduction to T Lymphocytes38m
- Major Histocompatibility Complex Molecules20m
- Activation of T Lymphocytes21m
- Functions of T Lymphocytes25m
- Review of Cytotoxic vs Helper T Cells13m
- Introduction to B Lymphocytes27m
- Antibodies14m
- Classes of Antibodies35m
- Outcomes of Antibody Binding to Antigen15m
- T Dependent & T Independent Antigens21m
- Clonal Selection20m
- Antibody Class Switching17m
- Affinity Maturation14m
- Primary and Secondary Response of Adaptive Immunity21m
- Immune Tolerance28m
- Regulatory T Cells10m
- Natural Killer Cells16m
- Review of Adaptive Immunity25m
- 22. The Respiratory System3h 20m
- 23. The Digestive System2h 5m
- 24. Metabolism and Nutrition4h 0m
- Essential Amino Acids5m
- Lipid Vitamins19m
- Cellular Respiration: Redox Reactions15m
- Introduction to Cellular Respiration22m
- Cellular Respiration: Types of Phosphorylation14m
- Cellular Respiration: Glycolysis19m
- Cellular Respiration: Pyruvate Oxidation8m
- Cellular Respiration: Krebs Cycle16m
- Cellular Respiration: Electron Transport Chain14m
- Cellular Respiration: Chemiosmosis7m
- Review of Aerobic Cellular Respiration18m
- Fermentation & Anaerobic Respiration23m
- Gluconeogenesis16m
- Fatty Acid Oxidation20m
- Amino Acid Oxidation17m
- 25. The Urinary System2h 39m
- 26. Fluid and Electrolyte Balance, Acid Base Balance Coming soon
- 27. The Reproductive System2h 5m
- 28. Human Development1h 21m
- 29. Heredity Coming soon
16. The Endocrine System
Introduction to the Endocrine System
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