● Nervous System○ Neurons~~electrical wires

● Endocrine system○ A bit slower○ Longer lasting○ Horomones○ Specific glands, hormones they secrete, where they're located, what happens

● Horomones○ Tiny molecules w specific shapes○ Chemical message○ Go to target cell○ Get message into cell so DNA can do its job

● Positive feedback ○ Milk release

● 2 types of glands in body○ Endocrine gland

■ Ductless■ Ducts bring message to bloodstream■ Endocrine sends message directly into bloodstream

○ Exocrine gland■ Products leave the body (aside from digestive enzymes)■ Sweat, saliva, digestive enzymes■ Reach location by means of ducts■ Pancreas is both

● As endocrine: regulates sugar going into blood● As exocrine: acts as digestive gland

● 3 kinds of hormones○ Steroid

■ Sex hormones■ Fat soluble, made from cholesterol■ Estrogen, testosterone

○ Amino acid■ Most frequently made from tyrosine■ Small, powerful■ Epinephrine (adrenaline)

○ Peptide■ Made of long chains of AA■ Most diverse group of hormones in the body■ Insulin

● Antagonistic hormone called glucagon● Antagonistic relationships

○ Effects of hormone often countered by another hormone○ Feedback mechanisms adjust balance of two hormones○ Example of homeostasis

● Pheramones○ Chemical signals, act like hormones○ Used between animals of same species for mating, territory, alarm signals○ Very strong, pass through the air○ Queen of honeybee comb releases pheromone that causes worker bees to settle

down● Local regulators

○ Affect target cells adjacent to their point of secretion○ Chemical signaling○ Not necessarily released by glands, can be released by cells

■ Paracrine signaling● Less direct, still very localized● Cell dispatches regulatory substances into surrounding interstitial

fluid● affecting only nearby cells● Ex: Histamines, Interleukins, growth factors, prostaglandins

■ Interleukins ■ Neurotransmitters

● Carry info from one neuron to another, or to different organs/cells● Synaptic signaling is most direct form of transmission

■ Growth factor ● Proteins and peptides● Must be present for cells to grow● produce an environment cells can grow into● Ex: embryonic neurons need NGF, EGF● Regulate development

■ Nitric Oxide ● Triggers changes in target cell● Functions ar neurotransmitter

■ Oncogenes ● Code for membrane proteins that function as receptors for that

factor● Do not require binding of a growth factor● Tissue grows abnormally● Malformed protein that sends inappropriate message that it

shouldn’t send○ Can be cell surface signal or diffusible ○ Can make cell grow when it should not

■ Prostaglandins (PG’s) ● Modified fatty acids have function in inflammatory response● Prost E and prots F have an antagonistic relationship

○ Have opposite effects on smooth muscle cells in walls of blood vessels serving the lungs

○ E causes them to relax, F signals them to contract

● In female reproductive system○ Cause muscles of cells to contract○ secreted by placenta, acts like a gland

● In defense mechanisms of invertebrates● Helps induce fever and inflammation

○ Mediators of the inflammatory response○ Aspirin can reduce these symptoms

● 2 possible pathways○ Receptor in plasma membrane triggers signal transduction

■ Hormone binds to receptor on membrane■ Results in response■ Cells are unresponsive to signal if they lack the appropriate receptors■ How chemical signal brings about changes in cell depends on where it

binds to a receptor● On target cell’s surface● Inside the cell

■ Most local regulators and hormones have plasma-membrane receptors● Signal receptor is first component of signal-transduction-

pathway● Same signal can bring about different changes in different cells● Peptide molecule

○ Needs a receptor to get across○ Sends out a message○ CAMP

■ Secondary messenger■ Picks up message from receptor, bring it to

nucleus, causes it to undergo gene expression■ Steroid hormones, thyroid hormones, some local regulators bind to

intracellular receptors● All small nonpolar molecules that can easily pass through● Intracellular receptors found inside nucleus● Pass through membrane, gins to receptor on nucleus, activates

DNA to turn on gene● Ex: ecdysone

○ Bring about molting in arthropods■ Diff effects on diff target cells

● A single type of molecules, like the neurotransmitter acetylcholine, can produce different responses in different target cells

● May result because○ Receptors are different○ Signal transduction pathways are different

● 2 classes of hormones○ Invertebrate hormones

■ Don’t use tropic hormones■ Help w/ reproduction, development, homeostasis■ Ex: ecdysone

● Triggers molting: growing out of skeleton● Work w/ brain hormones● Keeps body in balance● Controlled by brain hormone(BH)● BH and ecdysone are regulated by Juvenile Hormone (JH)

■ Steps:● 1) neurosecretory cells in brian produce BH, stored in corpus

cardiacum● 2) BH signals the prothoracic gland to produce ecdysone● Ecdysone secretion from gland is episodic● 4) juvenile hormone, secreted by corpus allatum, controls the

stages with its concentration○ Vertabrate horomones

■ Tropic Hormones - Stimulate other glands in body to work● LH, prolactin, FSH, ACTH, ● Build up of these tells the hypothalamus to stop

● Hypothalamus○ Receives info from nerves, initiates endocrine signals appropriate to

environmental conditions■ Hormone releasing cells are 2 sets of neurosecretory glands; secretions

stores in pituitary gland■ Neurosecretory cells help communicate w/ pituitary (uses neurons for

communication)■ Release different hypothalamic hormones to the anterior and posterior

gland● Releasing hormones

go to anterior pituitary● Inhibiting hormones

make anterior pituitary stop secreting hormones

○ Pituitary■ Stimulate to stop/ make certain

hormones■ At base of hypothalamus■ Anterior (adenohypophysis)

● Made of endocrine cells that make and secrete hormones directly into blood

● Every anterior pituitary hormones is controlled by at least 1 releasing hormone

■ Posterior (neurohypophysis)● Extension of the brain● Stores and secretes 2 hormones made by neurosecretory cells in

hypothalamus

● Posterior (back)○ Connected to hypothalamus by neurosecretory glands

■ Hormones sent via neurons into posterior pituitary■ Hormones made by hypothalamus

○ Oxytocin■ Peptide■ Induces labor, contracts uterus, makes breasts make milk

○ ADH■ Peptide■ antidiuretic hormone■ Induces re-absorption of h2o, message sent to kidneys ■ Stimulates kidneys to absorb water when dehydrated

● Increases water retention■ Uses negative feedback w/ hypothalamus to control water intake

● Anterior (front)○ Neurosecretory cells release hormones into capillary network

■ 4 are tropic hormones● Stimulate synthesis//release of hormones from other endocrine

glands○ TSH, ACTH, FSH, LH

● Others○ GH, PRL, MSH, endorphins

○ GH■ protein■ Promotes growth directly

● Cells and tissue■ Stimulates production of growth factors

● trophic hormone travels to liver, induces it to produce more cells ● Ex: IGF (insulinlike growth factors) secretion by the liver

○ Prolactin■ protein■ Has diff effects on diff animals

● Mammals-- helps produce milk● Brids--- helps regulate fat metabolism and reproduction● Amphibians--- aids in metamorphosis● Freshwater fishes-- regulates salt and water balance

○ FSH (follicle stimulating hormone)

■ glycoprotein■ Induces egg to grow, ovulation (when follicle breaks)■ Produces sperm in males■ Works with LH, both produced in hypothalamus■ gonandotropin

○ LH (luteinizing hormone)■ Glycoprotein ■ In ovulation, after follicle breaks, it causes broken follicle tissue to change

into a gland■ Changes into corpus luteum■ Produces hormones (estrogens and progesterone)■ LH is tropic hormone■ gonandotropoin

○ TSH (Thyroid stimulating hormone )■ glycoprotein■ Trophic horomone

● TSH affects thyroid● Makes thyroxin (T3, T4)

○ Remaining hormones made from pro-opiomelanocortin ■ Start off as long polypeptide chain, get cleaved into different hormones■ ACTH (Adrenocorticotropic hormone)

● Peptide● Stimulates production of steroid hormones (cortisone) by adrenal

cortex○ Stimulates adrenal glands on top of kidneys

■ MSH (Melanocyte stimulating hormone)● Peptide● Melanocytes are cells in your skin that give you color

○ Stimulates pigment activity○ Sun accelerates production of MSH--darker skin color

■ Endorphin● Peptide● Produced by neurons in brain● Inhibit pain perception

● Pineal Gland○ Near center of mammalian brain○ Secretes melatonin

■ Amine○ Contains light sensitive cells, melatonin regulates functions relates to light○ Affects skin pigmentation in vertebrates○ Secreted at night

● Thyroid gland○ 2 lobes; upper part of larynx○ Produces T3 and T4 Amine

■ made from tyrosine○ Negative feedback

■ TRH released by hypothalamus, stimulates TSH■ TSH stimulates gland to make T3 and T4

○ Thyroid plays role in maturation and development■ Big impact on metabolism■ Helps with metamorphosis in amphibians■ Also vital in homeostasis

○ Hyperthyroidism■ Make more thyroxine■ High body temp, blood pressure goes up■ Weight loss

○ Hypothyroidism■ Not enough thyroxine■ As a young child→ mental retardation■ As adult→ more prone to getting a cold

○ Goiter■ Deficiency disease■ Not getting enough of a vitamin, react to it■ If not getting enough iodine causes goiter■ Thyroid gland gets huge, sticks out

● Parathyroid glands ○ Four; embedded on surface of thyroid gland○ Helps regulate calcium levels○ Secretes PTH Peptide

■ Raises Ca in blood ■ Raises level of blood Ca by direct and indirect effects on bone and kidney

● In bone, PTH induces osteoblasts to decompose and release Ca● In kidneys, PTH stimulates absorption of Ca, activates vitamin D

○ If Ca level too high, thyroid gland secretes calcitonin Peptide■ Lowers Ca in blood ■ antagonistic relationship

○ Osteoblast■ When decomposed, increased level of Ca in bloodstreams■ Bone forming cells

~~~~~~~~~~~~~~~basically, THYROID releases CALCITONIN, increaces Ca+~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PARATHYROID releases PTH which stimulates Ca+ uptake~~~~~~~~~~~~

● Pancreas gland○ Next to stomach, empties into large intestine○ Mainly exocrine gland

■ Secretes digestive enzymes■ Go into digestive system, breaks down food■ Secretes bicarbonate, fixes pH

○ Small part related to endocrine■ Islets of Langerhans

● Clusters of endocrine cells in pancreas (alpha and beta)● Specialized cells with endocrine functions● Alpha cells

○ Secrete glucagon protein○ Helps to raise blood sugar

● Beta cells○ Secrete insulin protein○ Decrease glucose level

○ antagonistic relationship■ Work opposite each other, hand in hand■ Blood glucose concentration determines relative amounts of insulin and

glucagon secreted via negative feedback■ Vital to glucose homeostasis

○ Diabetes Mellitus■ I (Juvenile)

● Genetic; because of autoimmune problem, beta cells are destroyed, no insulin

○ Cells are not being encourage to take up glucose ○ Blood glucose levels remain high, cells are starving○ Solution is insulin shots

● autoimmune disorder● Immune system attacks and destroys Islets

■ II (more adult)● With bad lifestyle

○ Receptors are not working properly bc they have been in contact with too much glucose

○ No longer respond the way they should to insulin○ Solution is change in the diet

● Target cells are different shape● Insulin can’t cross membrane

■ Both diabetes● Increase blood sugar● Kidney sees there’s too much

glucose○ Gets rid of it via urine○ Body doesnt get any

sugar● Adrenal Glands

○ Located at top of kidney

○ 2 sections: cortex and medulla■ Secrete different hormones

○ Medulla■ inner■ Makes epinephrine and norepinephrine (Adrenaline; fight or flight

hormone) ■ Amine

○ Cortex■ Outter■ Stressful stimuli make the hypothalamus send ACTH to adrenal glands,

they make corticosteroids■ Aka cortisones

● Raise blood glucose, maintain salt and water balance● Promotes glucose synthesis● Watch salt and water balance

■ In another case of negative feedback, elevated levels of corticosteroids suppress secretion of ACTH

■ 3 groups● Glucocorticoids, mineralocorticoids, sex hormones

● Gonads○ Testes and ovaries○ Make 3 kinds of steroid hormones

■ Androgens steroid● Testosterone ● male reproduction system

■ Estrogens steroid● Estradiol● female reproductive system

■ Progestins steroid● Progesterone● Growth and development of embryo

○ Gonadotropins control synthesis of estrogens and androgens■ FSH & LH

● These are both controlled by GnRH● Other Places to Find Hormones

○ Digestive■ gastrin→ gastric juice

○ Kidneys■ Glands involved in production of red blood cells

○ Heart■ Muscle tissue produces hormones■ No gland for this■ Regulate salt and water balance

○ Brain■ Pineal gland

■ Secretes melatonin■ Reacts to amount of dark■ Circadian rhythm

● Your body clocks; knowing day from night, and recognized seasons

○ Neck■ Thymus gland

● Immune system● Helps with maturation of T-Lymphocytes

Human Systems – Sample EssaysDiscuss the sources and actions of each of the following pairs of hormones in humans and describe the feedback mechanisms that control their release. a. Insulin..glucagon

● If too high○ Beta cells of pancreas stimulates to release insulin

■ Insulin stimulates body cells to take up more glucose, liver takes up glucose

■ Blood level lowers○ If too low, alpha cells of pancreas stimulated to

release glucagon■ Glucagon stimulates liver to break down

glycogen into glucose, blood glucose level rises back up

b. Parathyroid hormone..calcitonin● If blood calcium level too low, parathyroid gland

releases parathyroid hormone (PTH)○ Blood calcium level rises○ Increaces Ca uptake in kidneys○ Stimulates ca release from bones

● If blood calcium level rises above setpoint, thyroid gland releases calcitonin

○ Stimulates Ca deposition in bones○ Reduces ca uptake in kidneys○ Blood calcium level falls

c. Thyrotropin (TSH) ..thyroxine (T4)● Hypothalamus secretes TRH (TSH releasing hormone)

○ Stimulates anterior pituitary to secretes TSH○ TSH binds to specific receptors in thyroid gland○ This stimulates T3 and T4 to be made

Biological recognition is important in many processes at the molecular, cellular, and organismal levels. Explain how the process of recognition occurs and give an example.

● Target cells respond to specific hormones● Receptor in plasma membrane triggers signal transduction

o Hormone binds to receptor on membraneo Results in responseo Cells are unresponsive to signal if they lack the appropriate receptorso How chemical signal brings about changes in cell depends on where it binds to a

receptor▪ On target cell’s surface▪ Inside the cell

o Most peptides have plasma-membrane receptors▪ Also local regulators and hormones Signal receptor is first component of signal-

transduction-pathway▪ Same signal can bring about different changes in different cells▪ Peptide molecule

● Needs a receptor to get across● Sends out a message● CAMP

o Secondary messengero Picks up message from receptor, bring it to nucleus, causes it to

undergo gene expression

o Steroid hormones bind to intracellular receptors▪ also thyroid hormones and some local regulators▪ All small nonpolar molecules that can easily pass through▪ Intracellular receptors found inside nucleus▪ Pass through membrane, gins to receptor on nucleus, activates DNA to turn on

gene▪ Ex: ecdysone

● Bring about molting in arthropodso Diff effects on diff target cells

▪ A single type of molecules, like the neurotransmitter acetylcholine, can produce different responses in different target cells

▪ May result because● Receptors are different● Signal transduction pathways are different

Hormones play an important role in regulating the lives of many living organisms.a) For TWO of the following physiological responses, explain how hormones cause the

response in animals.i. Increase in height

● GHa)

i. Adjustments to change in lightii. Adjustment to lack of water

b) Describe TWO different mechanisms by which hormones cause their effects at the cellular level.

Homeostasis, maintaining a steady-state internal environment, is characteristic of all living things. Choose three of the following physiological parameters and for each, describe how homeostasis is maintained by the organism of your choice. Be sure to indicate what animal you have chosen for each parameter. You may use the same animal or different animals for your three descriptions.Blood glucose levels--- Pancreatic- islets of langerhans---alpha and beta

● Mainly exocrine: not related to endocrineo Secrete digestive enzymes

▪ Strats to break down food in the intestine▪ Bicarbonate is excreted by the stomach, then carried to the small intestine via

pancreatic duct● Endocrine

o Islets of langerhans: specialized cells with endocrine functions▪ Secretes alpha and beta islets▪ Alpha secretes glucagon

● Stimulates liver to break down glycogen and release glucose into blood▪ Beta secretes insulin

● Decreases glucose level● Stimulates almost all body cells except the brain to take up glucose from

the blood

● Decreases blood glucose by slowing glycogen breakdown in liver and inhibiting the conversion of AA and glycerol to sugar

▪ Antagonistic: do the opposite of one another▪ Regulate the concentration of glucose in the blood

● Critical because glucose is a major fuel for cellular respiration ▪ Both peptide hormones▪ When blood glucose levels exceeds 90mg/100mL, insulin is released▪ When glucose level drops, glucagon increases glucose concentration▪ Negative feedback

pH of the blood● Buffer system

o calcium bicarbonate acts as buffer so when things travel, say from stomach to small intestine,

o sharp change in pH of the environments do not counteract each other▪ Calcium bicarbonate and phosphoric acid in the blood also ensure that it stays

at a normal pH of 7.4▪ if it fluctuates too high or too low, you will probably die

Osmotic concentration of the blood---ADH in pituitary● ADH (antidiuretic hormone)

o Absorbs watero Decreasing urine volumeo Sends messages to the kidney which absorbs the water and filters ito Regulate the osmolarity of the blood

▪ Monitored by a group of nerve cells that function as osmoreceptors in the hypothalamus

▪ When osmolarity of the plasma increases, these cells shrink slightly (due to osmosis) and transmit nerve impulses to certain neurosecretory cells

▪ Respond by releasing ADH▪ When it reaches the kidney, it binds to receptors on the surface of the cell lining

the collecting ducts▪ This activates a signal transduction pathway that increases the water permeability

of the collecting duct▪ Water exits and enters capillaries, helping prevent a further increasing blood

osmolarity above the set point▪ As more dilute blood arrives, the hypothalamus responds to the reduction in

osmolarity by slowly releasing ADH▪ Effects: increased water reabsorption in the kidneys, prevent overcompensation

by shutting off further secretion of the hormone and quenching thirst▪ Negative feedback