Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MCAT > Hormones, Neurotransmitters, Signaling Molecules > Flashcards

Hormones, Neurotransmitters, Signaling Molecules Flashcards

(56 cards)

Start Studying
1
Q

Somatostatin

A

Somatostatin: halts pro-digestion hormones- gastrin, secretin, CCK

also stalls stomach emptying and halts release of pancreatic insulin and glucagon

  • also inhibits growth hormone release

Empty stomach promotes appetite, inhibits digestion

Full stomach inhibits appetite and stimulates digestion

  • stomach acid and pancreatic secretion are stimulated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Antidiuretic Hormone (ADH) (Vasopressin)

A

Promotes water retention by increasing water reabsorption in collecting duct of kidneys

  • promotion of aquaporins in collecting duct cells

Vasoconstriction, increases blood pressure and volume

HOWEVER, reduces osmolarity of blood (no effect on solute)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Norepinephrine

Produced by?

A
  • stress hormone inhibits insulin, FIGHT OR FLIGHT

increases blood glucose levels

Produced by adrenal medulla (like epinephrine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Placenta secretes

A

Human chorionic gonadotropin (hCG) (pregnancy tests test for this)

  • Later progesterone and estrogen to maintain pregnancy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Glutamate

A

Neurotransmitter; excitatory, depolarizes neurons

  • most common neurotransmitter, 90% of neuronal connections in brain
  • learning and memory

Opposite of GABA

*Also an acidic amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Regulation of neurotransmission by exogenous chemicals (from outside the body)

A

Selective Serotonin Reuptake Inhibitors (SSRIs): treatment of depression

Monoamine Oxidase Inhibitors (MAOIs): anti-tuberculosis, anti-depressant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Thyroid secretes (3) hormones

A

Non tropic hormones T3 and T4 which increase metabolic rate

  • Hypothyroidism: slow metabolic rate - weight gain, fatigue
  • Hyperthyroidism: accelerates metabolic rate - weight loss, tachycardia

calcitonin: reduces calcium concentration in the blood stream

  • promotes storage of Ca in bone, increases urinary excretion of calcium
    • “toning down” calcium in blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Salivary amylase

Pancreatic amylase

Brush border disaccharides

Sucrase, maltase, lactase

A

Salivary amylase breaks starches into trisaccharides and disaccharides

  • Stomach doesn’t enzymatically digest carbs but does so mechanically, increasing surface area exposed to enzymes in small intestine

Cholecystokinin induces pancreatic digestive hormones when chyme enters duodenum

  • Pancreatic amylase hydrolyzes polysaccharides into di- and tri-

Brush border disaccharidases secreted by enterocytes in small intestine turn disaccharides into monosaccharides

sucrase: sucrose into glucose and fructose

maltase: maltose into two glucose

lactase: lactose into glucose and galactose

individuals deficient for lactase can’t digest lactose from milk/dairy

  • indigested lactose passes to large intestine and fermented by bacteria –> results in gas (bloating, discomfort, flatulence)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Testes and Ovaries respond to _____

From where?

Function?

A

Leutinizing Hormone and Follicle Stimulating Hormone from anterior pituitary to release testosterone in males and estrogen in women, help develop secondary sex characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Dopamine

A

Neurotransmitter; reward pathways and addiction

  • increased by psychoactive drugs, euphoria
  • mediates motor functions

loss of dopamine-secreting neurons in substantia nigra leads to Parkinsons disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

intracrine

A

signals travel the shortest distance

signals act within the cell that synthesizes them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

autocrine

A

signals are released, then bind to receptors on the cell that synthesized them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

juxtacrine

A

​signals travel between cells in close contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

paracrine

A

​signals travel between nearby cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

endocrine

A

signals (hormones) travel between distant cells via circulatory system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Parathyroid gland releases:

A

Release parathyroid hormone: opposes effects of calcitonin in order to increase calcium levels in blood

  • promotes calcium absorption in the intestines
  • reduces calcium storage in bone and calcium excretion in urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Estrogen is produced by

A

Ovarian follicle cells, corpus luteum formed from ruptured follicle cells, and placenta

(anterior pituitary forms GnRH which leads to production of estrogen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Amino acid derived hormones

A

Some behave like peptide hormones, some behave like steroids

Small molecules derived from a SINGLE amino acid

ex. T3 and T4 hormones derived from tyrosine - both hydrophobic, behave like steroid hormones w/ long lasting effects

Others like epinephrine and norepinephrine are water-soluble and act like peptide hormones - powerful but short lived

Some are amphipathic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Sleep/wakefulness

A

Circadian rhythm: 24 hr sleep/wake cycles

Pineal gland -> melatonin -> drowsiness

Adrenal cortex -> cortisol -> wakefulness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

secretin

A
  • regulation of gastric acid, regulation of pancreatic bicarbonate, and osmoregulation.

stimulates secretion of bicarbonate which quickly neutralizes acidic chyme (pH 6-7)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where are steroid hormones produced?

How are peptide hormones produced

A

Steroid hormones synthesized from cholesterol in the smooth ER and diffuse directly through cell membrane into bloodstream

Peptide hormones produced by transcription of relevant mRNA, translation into polypeptide –> preprohormone

  • preprohormone is secreted into rough ER and modified into prohormone –> golgi apparatus

in golgi, cleaved by peptidases and sometimes modified by glycosylation into peptide hormones

leave golgi in vesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

cAMP

A

Not a hormone- regulates pivotal physiologic processes including metabolism, secretion, calcium homeostasis, muscle contraction, cell fate, and gene transcription. cAMP is a cyclic nucleotide that serves as a vital second messenger in several signaling pathways.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

GnRH (gonadotropic releasing hormone

Corticotrophin-releasing hormone

Study These Flashcards
A

triggers LH and FSH reproductive hormones

promotes ACTH which releases cortisol from adrenal glands

24
Q

Vitamin D

Study These Flashcards
A

Help body absorb calcium and phosphorus

25
adrenal cortex secretes
**adrenal cortex**: secretes steroid hormones **corticosteroids ​** Release of corticosteroids is stimulated by **adrenocorticotropic hormone (ACTH) from anterior pituitary** **1. ​glucocorticoids (cortisol): sugar** * cortisol released in response to stress and low blood glucose, also suppresses inflammation **2. mineralocorticoids (aldosterone):** influence fluid and salt balance * aldosterone promotes fluid retention by increasing sodium reuptake **3. sex hormones (androgens and estrogens):** low level production, moreso in sex organs
26
Adrenal medulla secretes:
interior region of each gland surrounded by the cortex produces amino acid derived hormones epinephrine and norepinephrine **(catecholamines)** * sympathetic fight or flight * epinephrine used in Epi-Pens to treat anaphylaxis
27
Precursor for serotonin and melotonin
Tryptophan (Trp, W), aromatic amino acid - W = double ring
28
Histamine
Allergic response hormone (without endocrine gland in traditional sense) Histidine is precursor Released by basophils and mast cells (inflammatory cells)
29
Prolactin
Induces lactation Stress response, anxiety, depression, contributor to post-partum depression Produced by anterior pituitary gland, not triggered by hypothalamus
30
Hormones from anterior pituitary not tropically triggered by hypothalamus
Prolactin: acts on the mammary glands to stimulate milk production Endorphins: reduce reception of pain
31
Cortisol
**adrenal cortex:** secretes steroid hormones corticosteroids ​ Release of corticosteroids is stimulated by **adrenocorticotropic hormone (ACTH)** from anterior pituitary * in response to low blood glucose, also suppresses inflammation
32
GABA
Opposite of glutamate, **inhibitory** hyperpolarizes neurons * slow or block certain signals in the brain
33
Atrial Natriuretic Peptide
Produced by cardiomyocytes in heart in response to high blood pressure: to decrease blood pressure by triggering blood vessel dilation and excretion of sodium in urine
34
Aldosterone
aldosterone: secreted by adrenal cortex in response to low blood pressure, low sodium, sympathetic NS regulated by Renin-angiotensin-aldosterone system (RAAS) **promotes Na reabsorption, maintains osmolality**
35
HDL High Density Lipoprotein
Picks up stray cholesterol and other lipids and brings them back to the liver Cholesterol transporter High HDL = good cardiovascular health, decreased risk of **atherosclerosis:** unhealthy narrowing of blood vessels from plaque buildup
36
Acetylcholine
Neurotransmitter, muscle contractions also communicates signals between central NS and autonomic NS sends signals from parasympathetic neurons to target
37
Androgen
Testosterone
38
Estrogen:
estradiols, progesterone
39
Peptide hormones
Chains of amino acids, large and polar - Can't diffuse into cell, must interact via membrane receptors and secondary messengers (QUICK ONSET\< SHORT LASTING) * Steroid hormones diffuse through membrane, interact with cytosolic or nucleic receptors
40
Glucagon
Blood glucose is low, inhibits glycolysis, glycogenesis * Promotes glycogenolysis, gluconeogenesis Inhibits protein synthesis and allows proteins to be broken down * amino acids can be taken up by liver cells for new glucose molecules via gluconeogenesis
41
Skeletal hormones
**1. Parathyroid (PTH)-** released by parathyroid glands increases blood calcium promotes osteoclast bone resorption promotes absorption of dietary calcium in GI tract **2. Calcatriol-** derivative of vitamin D which the body manufactured at the skin in response to UV light increases blood calcium **3. Calcitonin-** secreted from thyroid gland in response to high blood calcium decreases blood calcium levels inhibits activity of osteoclasts reduce absorption of dietary calcium
42
Vitamins
Organic molecules with lots of carbon-hydrogen bonds * Often serve as coenzymes for essential processes ex. vitamin K a coenzyme in blood clotting Vitamin D in calcium reabsorption
43
Effect of glucagon on lipid breakdown
Glucagon promotes **lipolysis**: triglyceride breakdown * activates **protein kinase A** which activates hormone sensitive lipases in adipose tissue Increases fatty acid conc in blood glycerol can also be used for energy in liver and kidneys
44
3'-5' exonuclease activity
DNA repair
45
Thymus hormone
secretes thymosin, hormone that helps T cells develop and mature
46
Serotonin
Regulates mood, appetite, sleep, intestinal movement * current hypothesis is depression associated with low serotonin Antidepressants: **selective serotonin reuptake inhibitors (SSRIs)** * prevent serotonin from being taken up by neurons, stays in synapse longer
47
CCK:
stimulates release of digestive enzymes from pancreas and bile from gallbladder
48
How is glycogenolysis regulated differently in liver and skeletal cells? Whats the main enzyme?
**Glycogen phosphorylase** is regulated by **epinephrine hormone in skeletal cells** * when epinephrine binds to receptors on skeletal cells, kicks off signaling cascade which activated **glycogen phosphorylase** * releases **G1P** In the liver, **glucagon activates glycogen phosphorylase** to raise blood glucose when you haven't eaten in a while
49
Main enzyme for glycogenesis regulation?
**Glycogen synthase** (responsible for lengthening glycogen branches) * Insulin upregulated glycogen synthase, causing cells to make more glycogen
50
parasympathetic nervous system (PNS) releases the hormone
acetylcholine to slow the heart rate.
51
Vitamin A
Retinal and retinol * essential for vision interacts with opsin to form rhodopsin, which is present in the rods of the retina * Used for low light vision * Fat soluble
52
Deficiency in Vitamin C (ascorbic acid)
Common with sailors, no fresh food * scurvy: weakness, gum disease, excess bleeding, death Vitamin C required for collagen synthesis
53
How are peptide hormones produced
1. Peptide hormones produced by transcription of relevant mRNA, translation into polypeptide --\> **preprohormone** 2. preprohormone is secreted into **rough ER** and modified into **prohormone --\> golgi apparatus** * in golgi, cleaved by **peptidases** and sometimes modified by **glycosylation** into peptide hormones * leave golgi in vesicles
54
Neuroendocrine integration:
nervous system senses changes in environmental conditions and communicates to endocrine system
55
Endocrine regulates
Blood glucose Blood calcium Stress Fluid balance Metabolic rate Sexual development
56
What hormones besides glucagon and insulin affect blood sugar?
**Cortisol** (glucocorticoid released by adrenal cortex): increases blood glucose in fasting state by activating gluconeogenesis and glycogenolysis in the liver **Epinephrine** (adrenal medulla): raises blood sugar by stimulating glycogenolysis in liver and muscle cells; fight or flight response **Growth hormone:** increases blood glucose under intense physical stress or periods of growth and development

MCAT (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions