human anatomy more

When blood glucose levels rise, which specific cells are activated, and what hormone do they release?

Beta cells of the pancreas release Insulin.

what are the two main physical actions triggered by insulin to lower blood sugar?

Transport of glucose into body cells and storage of glucose as glycogen (in the liver).

What physical action is triggered by glucagon in the liver to raise blood sugar?

Breakdown of glycogen and release of glucose into blood.

What is the specific autoimmune mechanism that causes Type I diabetes?

The immune system destroys the beta cells of the pancreas, meaning no insulin is produced.

Unlike Type I, patients with Type II diabetes may still produce insulin. What is the underlying cellular problem?

The body's cells become insulin resistant or unresponsive over time.

What is the primary overarching function of the hypothalamus?

It provides integration between the nervous and endocrine systems.

When nervous signals trigger the hypothalamus, what specific types of cells do the work of translating that signal into a chemical release?

neurosecretory cells

Name the two specific non-tropic hormones that are released within the posterior pituitary.

ADH and oxytocin

How does the hypothalamus control the release of hormones from the anterior pituitary?

By releasing tropic hormones (HRH or HIH) that stimulate or inhibit it.

What do the acronyms HRH and HIH stand for?

Hypothalamic Releasing Hormone and Hypothalamic Inhibiting Hormone.

What two physical structures does Oxytocin target, and what actions does it cause in each? Is it tropic?

Non tropic, 1. Mammary glands: milk ejection, letdown. 2. Uterine muscles: contraction at birth.

Classify TSH (thyroid-stimulating hormone). What two specific hormones does it stimulate the thyroid to release?

It is Tropic. It stimulates the thyroid to release T3 and T4.

Classify ACTH (adrenocorticotropic hormone). What axis is it part of, and what does it force the adrenal cortex to release?

It is Tropic. It is part of the HPA axis (stress response) and stimulates the release of glucocorticoids (and mineralocorticoids).

How is GH (growth hormone) classified, and what physical structures does it directly stimulate to grow?

It is Both tropic and non-tropic. It directly stimulates tissue, bone, and cartilage growth.

Which specific cells within the thyroid gland manufacture T3 and T4?

Follicular cells.

What is the primary physiological function of T3 and T4 in the human body?

To stimulate metabolism (specifically the Basal Metabolic Rate, or BMR).

what are three specific internal or external stimuli that trigger the release of these thyroid hormones?

Low BMR, cold (or low levels of T3/T4), and stress.

In amphibians, what major developmental process is specifically stimulated by T4

metamorphosis => tadopole to frog tetrapod

Aside from maintaining bone density, list the four critical physiological processes that rely on blood calcium.

1. Synaptic transmission

2. Muscle contraction

3. Blood clotting

4. Immunity

Which specific cells produce Calcitonin, and which produce PTH (Parathyroid Hormone)?

Calcitonin is produced by Parafollicular cells (in the thyroid); PTH is produced by Chief cells (in the parathyroid).

Contrast the specific stimuli that trigger the release of Calcitonin versus PTH.

Calcitonin is triggered by high blood Ca²⁺. PTH is triggered by low blood Ca²⁺.

How does Calcitonin act to lower blood calcium levels?

It causes the inhibition of osteoclasts, which leads to a reduced release of Ca²⁺ from the bone into the blood.

What specific chemical class does testosterone belong to, and what exact cells produce it in males?

It is a steroid hormone (specifically an androgen) produced by Leydig cells. => androgens

what two fundamental reproductive structures require testosterone for their development?

Male genitalia and sperm.

What specific behavioral trait does testosterone help develop and maintain in both males and females ?

libido

How exactly does testosterone drive the physical adaptations we associate with strength training, such as increased muscle mass?

It promotes anabolism (protein synthesis)

what is the name of the tightly coiled tubes where sperm is actually produced?

Seminiferous tubule.

The seminiferous tubules are grouped into distinct, wedge-shaped sections. What is the bolded term for one of these sections?

Lobule

Once sperm leaves the tubules, it enters the comma-shaped structure on the outside of the testis to mature. What is the bolded name of this structure?

Epididymis

Where are Leydig cells located, and which specific hormone do they respond to?

Located in the lobule (interstitial space); they respond to LH (Luteinizing Hormone).

What is the primary product manufactured by Leydig cells?

Testosterone

Where are Sertoli cells located, and which specific hormone do they respond to?

seminiferous tubule; they respond to FSH (Follicle-Stimulating Hormone).

What are the two primary ways Sertoli cells physically support developing sperm?

They stimulate spermatogenesis and provide nutrients for spermatid differentiation.

What chemical class does estrogen belong to, and what is its principal active form?

It is a steroid hormone, and its principal form is estradiol.

Which primary organs produce estrogen, and what two specific structures within those organs are responsible?

Produced by the ovaries; specifically by the follicle and the corpus luteum

List the three secondary sexual characteristics established by estrogen as noted on the slide.

1. Breast development and fat deposits. 2. A wider pelvis (to allow passage for a baby). 3. Body hair.

During a single ovarian cycle, what two specific cells are produced when the primary oocyte completes Meiosis I?

A secondary oocyte and a polar body.

What is the specific name for the enlarged, mature follicle?

Graafian Follicle

what physical event defines ovulation, and where does the cell go?

The release of the secondary oocyte (with polar body) from its follicle into the oviduct.

What is the final biological outcome of the fusion of the sperm and ovum nuclei?

zygote

What are the 3 levels of control that coordinate the female reproductive cycle?

1. Hypothalamus

2. Anterior pituitary

3. Ovaries (Follicles & Corpus luteum)

The hormones from these three levels coordinate two distinct, connected physical cycles. What are they?

The Ovarian cycle (what happens in the ovary) and the Uterine cycle (what happens to the endometrial lining).

Which two pituitary hormones does the ovarian cycle respond to?

FSH, LH

What two major events in the ovary are specifically stimulated by LH?

Ovulation and corpus luteum formation.

How does the ovarian cycle physically "drive" the uterine cycle?

By producing estradiol and progesterone.

During the proliferative phase, which hormone acts alone to cause the repair and proliferation of the endometrium?

Estradiol only

What is the specific goal of the secretory phase, and which hormones work together to achieve it?

The goal is the preparation of the endometrium for potential implantation of a blastocyst, driven by estradiol and progesterone together.

True or False? Lymphatic system is tightly connected with interstitial fluids and blood

True

Why is blood classified as a connective tissue, and what acts as its liquid ground substance?

It consists of cells suspended in an extracellular matrix; its liquid ground substance is Plasma.

What are the 3 main functions of circulatory system

Transportation, Regulation, Protection

Explain the transportation functions of circulatory system

- Nutrients go from digestive system to body organs

- Gases from lungs to body organs to red blood cells

-hormones from endocrine/nervous to target organs

- wastes from metabolism -> kidneys

What four key factors does the circulatory system regulate?

1. pH

2. Body temperature

3. Osmotic pressure

4. Blood pressure

The circulatory system interacts tightly with the lymphatic system for protection. What two immune components does it carry?

Immune cells and antibodies.

Which two specific proteins are involved in the blood clotting function for protection?

Fibrinogen and fibronectin.

Where does the branch of the left coronary artery seen in the anterior view deliver oxygenated blood?

To the anterior walls of both ventricles and the interventricular septum.

What is the function of the coronary sinus, and where does it empty?

It removes CO2 and wastes from the heart muscle and empties into the Right Atrium.

What is the primary role of the Right coronary artery on the posterior surface?

It supplies cardiac cells with the oxygen and nutrients needed for constant contraction.

Function of ligamentum arteriosum

vessel that shunted blood from the pulmonary trunk to the aorta to bypass the fetal lungs.

What is the fossa ovalis

It is a depression in the interatrial septum

Which two structures are physically connected by the chordae tendineae?

The Atrioventricular (AV) valve cusps and the Papillary muscles.

Trace the path of blood coming from the body into the right side of the heart.

Vena cava (superior/inferior) -> Right atrium -> Atrioventricular valve -> Right ventricle -> Semilunar valve -> Pulmonary artery (to the lungs).

Trace the path of blood returning from the lungs into the left side of the heart.

Pulmonary veins -> Left atrium ->Atrioventricular valve -> Left ventricle -> Semilunar valve -> Aorta (to the body).

what is the function of the chordae tendineae on the atrioventricular valves?

They prevent the valves from swinging backwards (prolapsing) into the atria during ventricular contraction.

True or False, Aorta is the biggest artery in your body

True

Name the 3 sections of aorta

Ascending, Arch, Descending

Which two arteries are the very first to branch off the aorta, and where do they go?

The Right and Left Coronary Arteries; they supply the heart muscle itself.

In terms of pressure, when do the AV valves open?

When pressure in the atria is greater than pressure in the ventricles.

During ventricular contraction, what two structures prevent the AV valves from swinging backward into the atria?

Papillary muscles and tendons (chordae tendineae).

What causes the semilunar valves to close?

Ventricles relax and the backflow of blood from the arteries fills the valve pockets, snapping them shut.

What must happen for the semilunar valves to open?

Pressure from the ventricles must exceed the pressure in the arteries.

What is the clinical definition of a heart murmur?

An abnormal sound caused by turbulent blood flow, often due to a leaky or narrowed valve.

Mechanical function of valves

open and close based on pressure changes to ensure blood only flows in one direction

List the three layers of the heart wall from most superficial (outside) to deepest (inside).

1. Epicardium (Outer)

2. Myocardium (Middle)

3. Endocardium (Inner)

Which layer of the heart wall is composed of cardiac muscle and is responsible for contraction?

Myocardium

What type of tissue makes up the endocardium, and why is its smoothness important?

Squamous epithelium; it creates a smooth surface to reduce friction and prevent blood clotting inside the heart.

What is the name of the fibrous sac that encloses and protects the heart?

pericardium

The epicardium is a serous membrane. What is the primary function of a serous membrane in the heart?

To produce lubricating fluid that reduces friction during heart contractions.

What is myocardium composed of?

striated and branched myocardiocytes

Why is the branched nature of myocardiocytes important for heart function?

It allows a single cell to connect to multiple neighbors, forming a complex network that can contract together in a coordinated "squeeze."

What is myocardium joined by

intercalated disks

Why is signal transmission through gap junctions faster than in chemical synapses?

Because they allow direct ion flow from cell to cell, skipping the time-consuming steps of neurotransmitter release and binding.

gap junctions are equivalent to which type of synapse?

electrical synapses

Trace the path of deoxygenated blood (blue) from the heart to the lungs and back to the heart.

Right Ventricle -> Pulmonary Arteries -> Lung Capillaries -> Pulmonary Veins -> Left Atrium.

Trace the path of oxygenated blood (red) from the heart to the body and back to the heart.

Left Ventricle -> Aorta -> Systemic Capillaries (head/limbs/organs) -> Vena Cava (Superior/Inferior) -> Right Atrium.

where does blood go immediately after leaving the Digestive tract?

To the Liver via the Hepatic portal vein.

What event causes the "Lub" sound, and when does it occur?

The shutting of the AV valves at the beginning of Ventricular Systole (Phase 2/3 transition).

What event causes the "Dub" sound, and when does it occur?

The shutting of the semilunar valves at the end of Ventricular Systole (Phase 3/1 transition).

During the 0.4-second Atrial and Ventricular Diastole phase, what is the status of the heart chambers?

Both the atria and ventricles are relaxed, allowing blood to flow passively into the heart.

How long does Atrial Systole last, and what is its purpose?

0.1 seconds; it provides a final "squeeze" to push the remaining blood into the ventricles while they are in diastole.

Describe the status of the valves during the 0.3-second Ventricular Systole.

AV valves are shut (to prevent backflow) and Semilunar valves are OPEN (to allow blood to exit to the lungs/body).

Name the 3 steps of the cardiac cycle

1. Atrial and ventricular diastole

2. Atrial systole and ventricular diastole

3. Ventricular systole and atrial diastole

In the "Relaxation period," what is the mechanical state of the atria and the ventricles?

Both are in diastole (relaxing), allowing the heart to fill with blood.

During "Ventricular systole," where is blood being ejected?

Into the Aorta (from the left ventricle) and the Pulmonary Trunk (from the right ventricle).

Heart rate def

number of beats(cycles) per minute

What is the mathematical formula for calculating Cardiac Output?

Heart rate x stroke volume

What is the definition of Cardiac Output (CO)?

The total volume of blood pumped by the heart (specifically the left ventricle) every minute.

Define Stroke Volume and specify which chamber is the primary focus.

The amount of blood (in mL) ejected by the left ventricle during a single contraction (one beat).

What is the first structure in the heart's conduction system

SA Node(sinoatrial)

Name the full conduction pathway of heart

SA node -> Atrioventricular node -> AV Bundle of His -> Right and left branches -> purkinje fibers

Which chamber of the heart contains the SA node and AV node in its walls?

Right atrium