BIOL 318 Test 2 Study Guide Questions

endocrine vs exocrine glands

Endocrine glands secrete chemicals ( hormones) into the blood stream while exocrine glands secrete into ducts leading to body cavities or open spaces, epithelial surface

Types of cell communication

direct, paracrine, endocrine, synaptic

Types of Stimulation for Hormone Secretion

1. Hormonal

2. Humoral

3. Neural

hormonal stimuli

Hormones stimulate other endocrine organs to release their hormones

humoral stimuli

secretion of hormones in direct response to changing blood levels of ions and nutrients

neural stimuli

Nerve fibers stimulate hormone release

Sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines

classes of hormones

steroids, monoamines, and peptides

steroid hormones

enter the target cells and have a direct effect on the DNA of the nucleus; hormones secreted by the adrenal cortex, derived from cholesterol

Monoamines

dopamine, norepinephrine, serotonin

Peptides

Chains of amino acids that can function as neurotransmitters or hormones.

Transport of hormones in the blood

through the blood stream, hormones only affect a target cell

transport of hydrophilic hormones

Peptides, catecholamines

Dissolved in plasma

they bind with receptors on the outer cell membrane surface.

transport of hydrophobic hormones

Steroids, thyroid hormones

Bound to carrier proteins

Only free hormone can bind to receptors

Only free hormone can be metabolized

Longer half-life

Steroids enter cells by...

Steroid hormones are believed to enter cells solely by free diffusion through the plasma membrane.

Peptides enter cell by...

Unlike lipid-soluble hormones, peptide hormones cannot enter the target cell directly because they are insoluble in the lipid bilayer of the cell membrane. Instead, the receptors for peptide hormones are on the surface of the cell membrane of target cells.

Monoamines enter the cell by...

They may enter the presynaptic neuron primarily via plasma membrane transporters, such as the dopamine transporter (DAT), norepinephrine transporter (NET), and serotonin transporter (SERT).

Action of Hormones

-Circulate through bloodstream and affect only the target cells (have receptors)

-Hormones themselves are just triggers

gene activation

uncoiling DNA and temporarily removing histones

second messenger systems

Biochemical pathways that use second messengers to mediate intercellular signaling.

cAMP

In the field of molecular biology, the cAMP signaling pathway, also known as the adenylyl cyclase pathway, is a G protein-coupled receptor-triggered signaling cascade used in cell communication.

IP3 and DAG

IP3 is a second messenger molecule utilized in signal transduction in biological cells together with diacylglycerol (DAG).

How do cells upregulate sensitivity

The more receptors a cell has that are tuned to the message, the more the cell will respond to it. Receptors are created, or expressed, from instructions in the DNA of the cell, and they can be increased, or upregulated, when the signal is weak

How do cells downregulate sensitivity?

cellular decrease in the expression of a specific receptor in response to its increased activation by a molecule, such as a hormone or neurotransmitter, which reduces the cell's sensitivity to the molecule. This is an example of a locally acting (negative feedback) mechanism

How and where are hormones cleared/removed?

They are either destroyed by the liver or the actual tissues of the target organs. They are then removed by the kidneys.

hypothalamic-anterior pituitary pathway

Hypothalamic releasing and inhibiting hormones travel through a primary capillary plexus to the portal veins, which carry them into the anterior pituitary. Hormones produced by the anterior pituitary (in response to releasing hormones) enter a secondary capillary plexus, and from there drain into the circulation.

· hypothalamic-posterior pituitary pathway

the posterior lobe is connected to the hypothalamus by a bridge of nerve axons called the hypothalamic-hypophyseal tract, along which the hypothalamus sends hormones produced by hypothalamic nerve cell bodies to the posterior pituitary for storage and release into the circulation.

hypophyseal portal system

blood leaving capillary beds in hypothalamus travels to a capillary bed in anterior pituitary to allow for paracrine secretion of releasing hormones

Hormones of hypothalamus traveling to anterior pituitary gland

The thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone (GnRH), growth hormone-releasing hormone (GHRH), corticotropin-releasing hormone (CRH), somatostatin, and dopamine are released from the hypothalamus into the blood and travel to the anterior pituitary

Thyrotropin-releasing hormone (TRH)

Promotes secretion of thyroid-stimulating hormone (TSH) and prolactin (PRL); target organ-thyroid gland

Gonadotropin-releasing hormone (GnRH)

Promotes secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

Corticotropin-releasing hormone (CRH)

Promotes secretion of adrenocorticotropic hormone (ACTH)

Somatostatin

hormone that inhibits release of growth hormone and insulin

Dopamine

A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.

· Hormones of hypothalamus traveling to posterior pituitary gland

antidiuretic hormone (ADH) and oxytocin. These two hormones are stored in the posterior pituitary gland.

antidiuretic hormone (ADH)

Hormone produced by the neurosecretory cells in the hypothalamus that stimulates water reabsorption from kidney tubule cells into the blood and vasoconstriction of arterioles.

Oxytocin

A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.

Adrenocorticotrophic hormone (ACTH)

a pituitary hormone that activates the adrenal cortex to release corticosteroids (cortical steroids)

Thyroid Stimulating Hormone (TSH)

stimulates secretion from thyroid gland

Luteinising hormone (LH)

a glycoprotein hormone that is co-secreted along with follicle-stimulating hormone by the gonadotrophin cells in the adenohypophysis (anterior pituitary)

Follicle-stimulating hormone (FSH)

helps control the menstrual cycle and stimulates the growth of eggs in the ovaries

Prolactin (PRL)

secreted by the anterior lobe of the pituitary gland; promotes milk secretion

Growth Hormone (GH)

regulates the growth of the body

melanocyte-stimulating hormone (MSH)

increases the production of melanin in melanocytes of the skin

pineal gland

secretes melatonin

thyroid gland

produces hormones that regulate metabolism, body heat, and bone growth

TH production pathway and feedback loop

The Thyroid Feedback Mechanism. TH regulates TRH gene expression and production through a negative feedback mechanism; TRH expression is high when TH levels are low, and TRH expression is suppressed when TH levels are increased.

parathyroid glands

small pea-like organs that regulate calcium and phosphate balance in blood, bones, and other tissues

Thymus

An immune organ located near the heart. THe thymus is the site of T cell maturation and is larger in children and adolescents.

thymus Role in immune system development

The thymus produces hormones that regulate T-cell maturation and serves as the incubator against infections. It forms part of the immune system and it is positioned in the upper part of the chest known as the breastbone.

Different layers of the thymus

It is bilobed and has two subcomponents: the cortex and the medulla

adrenal glands

a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.

zona glomerulosa

The zona glomerulosa (sometimes, glomerular zone) of the adrenal gland is the most superficial layer of the adrenal cortex, lying directly beneath the renal capsule. Its cells are ovoid and arranged in clusters or arches (glomus is Latin for "ball"); secretes aldosterone

zona fasciculata

glucocorticoids (cortisol); The zona fasciculata constitutes the middle and also the widest zone of the adrenal cortex, sitting directly beneath the zona glomerulosa.

zona reticularis

secretes androgens; the innermost layer of the adrenal cortex, lying deep to the zona fasciculata and superficial to the adrenal medulla

Angiotensin pathway

Decreased cardiac output & blood pressure

Renin release

Turns Angiotensinogen into Angotensin I

Angiotensin II

Aldosterone

Salt and water retention

-> increased venous return

Pancreas

An organs in the abdominal cavity with two roles. The first is an exocrine role: to produce digestive enzymes and bicarbonate, which are delivered to the small intestine via the pancreatic duct. The second is an endocrine role: to secrete insulin and glucagon into the bloodstream to help regulate blood glucose levels.

Different types of cells in pancreas

The endocrine portion is arranged as discrete islets of Langerhans, which are composed of five different endocrine cell types (alpha, beta, delta, epsilon, and upsilon) secreting at least five hormones including glucagon, insulin, somatostatin, ghrelin, and pancreatic polypeptide, respectively

alpha cells of pancreas

secrete glucagon

beta cells of pancreas

secrete insulin

delta cells of pancreas

secrete somatostatin

epsilon cells of pancreas

secrete ghrelin

upsilon cells of pancreas

secrete pancreatic polypeptide

islets of Langerhans

cell clusters in the pancreas that form the endocrine part of that organ

Ovaries

Glands that produce the egg cells and hormones

Testes

male gonads

Types of Diabetes

type 1 and type 2

type 1 diabetes mellitus

diabetes in which no beta-cell production of insulin occurs and the patient is dependent on insulin for survival

type 2 diabetes

Diabetes of a form that develops especially in adults and most often obese individuals and that is characterized by high blood glucose resulting from impaired insulin utilization coupled with the body's inability to compensate with increased insulin production.

GH disorders

gigantism, dwarfism, acromegaly

Gigantism

a condition produced by hypersecretion of growth hormone during the early years of life

Dwarfism

congenital hyposecretion of growth hormone; hypopituitary dwarfism

acromegaly

abnormal enlargement of the extremities

TH disorders

hypothyroidism and hyperthyroidism

Hypothyroidism

condition of hyposecretion of the thyroid gland causing low thyroid levels in the blood that result in sluggishness, slow pulse, and often obesity

Hyperthyroidism

overactivity of the thyroid gland, resulting in a rapid heartbeat and an increased rate of metabolism.

PTH disorders

- Hypoparathyroidism

- Hyperparathyroidism

Hypoparathyroidism

hyposecretion of the parathyroid glands; symptoms include: a tingling sensation (paraesthesia) in your fingertips, toes and lips.

twitching facial muscles.

muscle pains or cramps, particularly in your legs, feet or tummy.

tiredness.

mood changes, such as feeling irritable, anxious or depressed.

dry, rough skin.

coarse hair that breaks easily and can fall out.

hyperparathyroidism

hypersecretion of the parathyroid glands, usually caused by a tumor; symptoms include Weak bones that break easily (osteoporosis)

Kidney stones.

Excessive urination.

Stomach (abdominal) pain.

Tiring easily or weakness.

Depression or forgetfulness.

Bone and joint pain.

Frequent complaints of illness with no clear cause.

Turner Syndrome

A chromosomal disorder in females in which either an X chromosome is missing, making the person XO instead of XX, or part of one X chromosome is deleted.

divisions of the respiratory system

upper respiratory tract and lower respiratory tract

upper respiratory tract

consists of the nose, mouth, pharynx, epiglottis, larynx, and trachea

lower respiratory tract

larynx, trachea, bronchi, lungs

Conducting vs respiratory zone

The conducting zone, which includes everything from the nose to the smallest bronchioles, moves air into and out of the lungs. The respiratory zone includes the respiratory bronchioles and alveoli and moves the respiratory gases, that is oxygen and carbon dioxide, in and out of the blood

Upper vs lower respiratory system

UPPER

- mouth

- nose

- sinus

- pharynx

- larynx

LOWER

- trachea

- lungs

function of mouth and nose in respiration

inhalation/exhalation

function of sinuses

Lighten the skull

Act as resonance chambers for speech

Produce mucus that drains into the nasal cavity

Pharynx

throat; passageway for food to the esophagus and air to the larynx

Larynx

voice box; passageway for air moving from pharynx to trachea; contains vocal cords

Trachea (windpipe)

passageway for air to the bronchi

Lungs function

Contains alveolus where gas exchange occurs

Pathway of air entering and exiting respiratory system

Pathway of air: nasal cavities (or oral cavity) > pharynx > trachea > primary bronchi (right & left) > secondary bronchi > tertiary bronchi > bronchioles > alveoli (site of gas exchange)

Alveoli

tiny sacs of lung tissue specialized for the movement of gases between air and blood

type 1 cells in alveoli

simple squamous epithelium, gas exchange

Type 2 cells (alveoli)

Reduce surface tension by secreting surfacant

dust cells (alveolar macrophages)

macrophages found between the alveoli that gobble up fine-particle debris

Why so many small alveoli and not one large alveolus?

To increase the exchange of gases in the lungs, alveoli are uncountable in number. They are too tiny to fit in alveolus numbers and boost gas exchange. The body can absorb much more oxygen than just two enormous ' empty bags '

What are the three respiratory groups of the brain?

The respiratory center is composed of three distinct neuronal groups in the brain: the dorsal respiratory group (DRG) in the nucleus tractus solitarius, the ventral respiratory group (VRG) in the medulla, and the pontine respiratory group in the pons.

dorsal respiratory group (DRG)

A portion of the medulla oblongata where the primary respiratory pacemaker is found.

ventral respiratory group (VRG)

A portion of the medulla oblongata that is responsible for modulating breathing during speech.

pontine respiratory group

transmit impulses to VRG to fine-tune breathing rhythms