Animals - Endocrine System

What is the endocrine system?

networks of glands and organs that control and maintain the body, produces/stores/releases hormones directly into the bloodstream to regulate vital bodily functions

What are 5 things the endocrine system controls?

metabolism, growth, reproduction, sleep, mood

Hormone

molecules that regulate processes in the body by signaling organs and tissues, chemical messengers

What are some examples of hormones?

corticosteroids, insulin, estrogen, epinephrine, testosterone, melatonin, dopamine

Hormones are produced by glands and organs. What is an endocrine gland?

small vascularized ductless glands composed of groups of cells arranged in cords or clumps

Why are endocrine glands highly vascularized?

need lots of oxygen to travel to all parts of the body via blood

How are hormones transported through the body by blood or fluid around cells?

interstitial fluid

How do hormones reach cells?

through receptores in cell membranes

How is the endocrine system controlled? What is that?

negative feedback loop: pattern in which output is constantly compared to setpoint

Nuerotransmitter

chemical messengers that allow neurons to communicate, passing signals to other neurons, muscles, or glands

T/F: Certain hormones can function as neurotransmitters.

true

Describe endocrine systems in invertebrates.

chemical signalsmust move from source to target cells via interstitial fluids rather than circulating blood, most dont have traditional endocrine system, rely on neurosecretory cells

Neurosecretory Cells

specialized nerve cells capable of synthesizing and secreting hormones or hormone like molecules

Describe the endocrine system in phylum porifera (sponges).

hormone like molecules that function in cell to cell signlaing

Describe the endocrine system in phylum cnidaria (jellyfish).

neuroendocrine cells that function in signaling

Describe the endocrine system in phylum platyhelminthes (flatworms).

neurosecretory cells

Describe the endocrine system in phylum annelida (segmented worms).

neurosecretory with ganglion (brain) serving as the main source of hormones

Describe the endocrine system in phylum nematoda (roundworms).

neurosecretory cells

Describe the endocrine system in insects.

use hormones to control molting and transitioning to different life stages

What are the three hormones insects use?

ecdysone, juvenile hormone (JH), prothoracicotropic hormone (PTTH)

Ecdysone

produced by prothoracic gland and intiates molting

Juvenile Hormone (JH)

maintains immature tissues, suppresses expression and development of adult tissues

PTTH (prothoracicotropic hormone)

stimulates the prothoracic gland

Vertebrate endocrine systems have many different glands, name some.

hypothalamus & pituitary, thyroid, adrenal glands, pancreas, reproductive organs (ovaries, testes)

Hypothalamus & Pituitary Gland

located in brain, control other glands, manage growth/water retention/pain, pituitary gland produces hormones involved in many different processes

Thyroid Gland

located in neck, produces hormones that control metabolic rate/heart rate/temp/energy usage, regulates growth/physical maturation, produces hormones: triiodothyronine (T3), thyroxine (T4), calcitonin

T3 and T4 impact what in frogs?

growth and metamorphosis

Adrenal Glands

sit atop the kidneys, regulate metabolism/blood pressure/immune system function/stress responses, produce various steroids, cortisol influences food metabolism/inflammation/stress, aldosterone promotes reabsorption of sodium and secretion of potassium in kidneys

Pancreas

located in upper abdomen, mangaes blood sugar using insulin/glucagon, insulin breaks down glucose, produces enyzmes to break down carbs, fats, proteins

T/F: The activty of glands and hormones in vertebrates are made of simple pathways.

false