Endocrine System Refresher for Med-Surg I

Heather Murphy

Welcome to the NSG3037 Adult Medical Surgical 1 Podcast series. I am Professor Heather Murphy. Each episode will cover topics we will discuss in class and you will see in your ATI assignments. The purpose of this podcast series is to supplement your learning and provide you with additional tools you can listen to "on the go" or simply doing things around the house. Today I am joined by 3 others who will help me untangle the endocrine system for Med-Surg I. The Key Points document uploaded in week 1 content of your course shell is the basis for this discussion, so if you have that handy, you can follow along and take notes if that helps you. Let’s start big picture: hormones are chemical messengers, and they exert their effects on specific target tissues.

Derek Mendoza

Hello, my name is Derek Mendoza and I am a registered nurse. I agree that the “specific” piece really matters. The way I explain it to my students is this lock-and-key idea. The hormone is the key, the receptor on the target cell is the lock, and if they don’t match, the door just doesn’t open.

Caitlin Hope

Hi, everyone! My name is Caitlin Hope and I've been a Registered Nurse for 2 years on a burn-trauma unit. In burn-trauma we see what happens when that messaging system goes off the rails. But normally, the body’s using feedback mechanisms to keep hormone levels in range.

Karen Whitaker

Welcome, students. I'm Karen Whitaker and I'm also a seasoned RN. From my experience, the regulation of hormone levels really depends on feedback. With negative feedback, the gland responds by increasing or decreasing secretion based on what’s happening in the body. So if a hormone level gets high, the gland gets the “okay, back off” signal.

Karen Whitaker

And then you’ve got positive feedback, which is rarer. There, increasing hormone levels cause another gland to release a hormone that actually stimulates further release of the first hormone. So instead of “enough, stop,” it’s “more, more, more” until something else shuts it down.

Derek Mendoza

What ties this all together is that neuroendocrine connection. The hypothalamus and the pituitary integrate communication between the nervous and endocrine systems. So they’re kind of the bridge between “fast” nerve signals and “slower but longer-acting” hormones.

Caitlin Hope

And then from the pituitary, we’ve got those anterior tropic hormones. They’re called “tropic” because they regulate secretion from other glands. So: thyroid-stimulating hormone, or TSH, tells the thyroid to secrete thyroid hormones.

Heather Murphy

Adrenocorticotropic hormone, ACTH, stimulates the adrenal cortex to secrete corticosteroids. Then follicle-stimulating hormone, FSH, stimulates estrogen secretion plus development of ova in women, and sperm in men.

Karen Whitaker

And luteinizing hormone, LH, is your ovulation trigger in women and also stimulates sex hormone secretion in both men and women. Then growth hormone, GH, is kind of the global player. Because it affects protein, lipid, and carbohydrate metabolism, it ends up impacting all body tissues.

Derek Mendoza

The posterior pituitary is a little different. It releases antidiuretic hormone, ADH, which regulates fluid volume by stimulating reabsorption of water in the kidneys. So when ADH is high, you hang on to water.

Caitlin Hope

And oxytocin, the other big posterior pituitary hormone, stimulates ejection of milk into mammary ducts and contraction of uterine smooth muscle. So, very focused target tissues, but huge implications when those levels change.

Heather Murphy

Don’t forget the pineal gland in this control-picture, too. It secretes melatonin and helps regulate circadian rhythm and reproduction. So even sleep–wake patterns are tied into endocrine control.

Karen Whitaker

Now, layer aging on top of all that. Normal aging results in decreased hormone production and secretion, altered metabolism and biologic activity of hormones, decreased responsiveness of target tissues, and changes in circadian rhythms.

Derek Mendoza

And that’s where assessment gets tricky. Those subtle aging changes can mimic manifestations of endocrine disorders. And the reverse is true—endocrine disorders can look like “just aging” if we’re not careful.

Caitlin Hope

So in practice, when an older adult says, “I’m just slowing down,” we have to keep in the back of our minds, “Is this age, or is there an under-treated endocrine issue here?”

Heather Murphy

Exactly. As nurses, understanding that big-picture control system, and how aging blurs the lines, helps us know when we need to dig deeper instead of just writing symptoms off as “normal.”

Karen Whitaker

Let’s zoom in on the big Med-Surg glands you’re gonna see every day: thyroid, parathyroids, adrenals, and pancreas. Starting with the thyroid—its major function is production, storage, and release of thyroid hormones: thyroxine, or T4, and triiodothyronine, T3.

Derek Mendoza

And iodine is required for those hormones to be synthesized. So if there’s not enough iodine available, the thyroid can’t make T3 and T4 the way it should.

Caitlin Hope

T3 and T4 affect metabolic rate, carbohydrate and lipid metabolism, growth and development, and nervous system activities. Which is why thyroid problems can look like changes in weight, energy, mood, even how fast someone’s thinking.

Heather Murphy

The thyroid also makes calcitonin. That’s produced by C cells, or parafollicular cells, in response to high circulating calcium levels. It’s part of the body’s calcium-regulation system.

Karen Whitaker

On the other side of that seesaw are the parathyroid glands—four small, oval structures usually arranged in pairs behind each thyroid lobe. They secrete parathyroid hormone, PTH, which regulates the blood level of calcium.

Derek Mendoza

So if you’re taking care of a patient post–thyroid surgery, for example, and their calcium starts dropping, that can be related to those tiny parathyroids being affected. Calcium changes there are not a side note—they’re central.

Caitlin Hope

Moving down to the adrenals: each adrenal gland sits on the upper part of a kidney, and they’re highly vascularized. They’ve got two main parts—the medulla and the cortex—that behave really differently.

Heather Murphy

The adrenal medulla secretes the catecholamines: epinephrine, which is the major one, norepinephrine, and dopamine. Those are key players in stress responses. Then the adrenal cortex secretes several steroid hormones: glucocorticoids, mineralocorticoids, and androgens.

Karen Whitaker

Cortisol is the main glucocorticoid. It helps regulate blood glucose concentration, inhibits inflammatory action, and supports the stress response. So when we think “stress hormone,” cortisol is front and center.

Derek Mendoza

Aldosterone is a potent mineralocorticoid that maintains extracellular fluid volume. So that’s your fluid and electrolyte balance—very relevant when you’re watching blood pressure, edema, all of that on the floor.

Caitlin Hope

And the small amounts of androgens that the cortex secretes are converted to testosterone in men and estrogen in women in peripheral tissues. So even though the amounts are small, they still contribute to overall sex hormone balance.

Heather Murphy

Alright, pancreas time. The pancreas secretes several hormones, and the big two for us in Med-Surg are glucagon and insulin.

Karen Whitaker

Glucagon is a catabolic hormone. when glucagon is active, the body’s breaking down stores to raise glucose.

Derek Mendoza

Insulin, in contrast, is an anabolic hormone. It’s the principal regulator of the metabolism and storage of ingested carbohydrates, fats, and proteins. So it helps move nutrients into cells and promotes storage instead of breakdown.

Caitlin Hope

So when you’re caring for Med-Surg patients—whether it’s someone with surgery stress, infection, or just NPO status—you’re always watching that balance between glucagon-driven “let’s raise glucose” and insulin-driven “let’s store and use it appropriately.”

Heather Murphy

And when those systems go off—thyroid, parathyroids, adrenals, pancreas—you see it in everything from vital signs to wound healing to mental status. Knowing the normal roles makes those abnormal patterns so much easier to catch.

Karen Whitaker

Let’s wrap with what nurses actually do at the bedside: assessment. Hormones affect every body tissue, so signs and symptoms of endocrine dysfunction can be all over the map.

Derek Mendoza

Yeah, and dysfunction can come from a lot of places—deficient secretion, excess secretion, problems with how hormones are transported, an inability of the target tissue to respond, or inappropriate stimulation of those target-tissue receptors.

Caitlin Hope

So history-taking really matters. We want a history of growth and development, weight distribution and changes, and then compare those to what we’d expect as normal for that person.

Heather Murphy

You also ask about the use of hormone replacements, previous hospitalizations, surgery, chemotherapy, and radiation therapy—especially to the head and neck. Those can all impact the glands themselves or their blood supply.

Karen Whitaker

Clinically, nurses also commonly ask focused questions about weight and energy changes, heat or cold intolerance, increased urination or thirst, menstrual patterns, and sexual function—because those are classic ways endocrine issues can show up in day-to-day life.

Derek Mendoza

And we can’t ignore mental and emotional status. The text points out that disorders can cause changes there, so someone who seems more depressed, anxious, or foggy than usual might have an endocrine piece to their story.

Caitlin Hope

Most endocrine glands are inaccessible to direct exam, so we focus on manifestations. We note the color and texture of the skin, hair, and nails, palpate the skin for texture and moisture, and inspect hair distribution patterns, including in the genital area.

Heather Murphy

Thyroid assessment gets its own little routine. When inspecting, you first observe in the normal position, preferably with side lighting, then with the neck in slight extension, and then while the patient swallows a sip of water.

Karen Whitaker

When you palpate the thyroid, you’re assessing size, shape, symmetry, tenderness, and any nodules. And there’s a safety caveat: only an experienced clinician should palpate an enlarged thyroid gland.

Derek Mendoza

We also assess the size, shape, symmetry, and general proportion of the hands and feet. Changes there over time can point toward long-standing endocrine conditions.

Caitlin Hope

On the diagnostic side, most tests involve blood and urine. We can either directly measure hormone levels or look indirectly at what those hormones do—things like electrolytes or glucose as a reflection of gland function.

Heather Murphy

Timing matters too. For hormones with circadian or sleep-related secretion, you need to note the sample time on the lab slip and on the sample itself. Otherwise, a “normal” fluctuation could be misread as a problem—or vice versa.

Karen Whitaker

For anterior pituitary function, commonly used labs include GH, prolactin, FSH, LH, TSH, and ACTH levels. That gives you a snapshot of how that master gland is behaving.

Derek Mendoza

And for thyroid, tests to assess abnormal function include TSH—which is the most common—total T4, free T4, and total T3. In practice, those often pair with your physical assessment and history to complete the picture.

Caitlin Hope

And of course, for everyday Med-Surg patients we’re constantly watching basic labs like glucose and electrolytes, because they’re often indirectly telling us how the endocrine system is doing under stress.

Heather Murphy

So to pull it together, assessment is really about patterns over time—history, physical, and labs, all lined up with what we know about each gland.

Karen Whitaker

Alright, I think that’s a solid endocrine primer.

Derek Mendoza

Yeah, I feel like we just walked through the control center, the major glands, and what we actually look for as nurses.

Caitlin Hope

And hopefully made it a little less intimidating for anyone heading into that first endocrine-heavy exam or clinical.

Heather Murphy

We’ll keep building on this in future episodes, digging into specific disorders and interventions.

Karen Whitaker

Thanks for hanging out with us today. Derek, Caitlin, Heather—always a pleasure.

Derek Mendoza

Same here, Karen. Bye everyone.

Caitlin Hope

Take care, y’all. See you next time.

Heather Murphy

Bye, everyone—keep growing, future nurses.