Hormones and the Endocrine System

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It is marked by elevated blood glucose levels.

Type I diabetes mellitus (insulin-dependent) is an autoimmune disorder in which the immune system destroys pancreatic beta cells.

Type II diabetes mellitus (non-insulin-dependent) involves insulin deficiency or reduced response of target cells due to change in insulin receptors.

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The endocrine and nervous systems act individually and together in regulating animal physiology

Signals from the nervous system initiate and regulate endocrine signals.

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Coordination of Endocrine and Nervous Systems in Invertebrates

In insects, molting and development are controlled by a combination of hormones:

A brain hormone stimulates release of ecdysone from the prothoracic glands

Juvenile hormone promotes retention of larval characteristics

Ecdysone promotes molting (in the presence of juvenile hormone) and development (in the absence of juvenile hormone) of adult characteristics

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Hormonal regulation of insect development

Ecdysone

Brain

PTTH

EARLY LARVA

Neurosecretory cells

Corpus cardiacum

Corpus allatum

LATER

LARVA

PUPA

ADULT

Low

JH

Juvenile

hormone

(JH)

Prothoracic

gland

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Coordination of Endocrine and Nervous Systems in Vertebrates

The hypothalamus receives information from the nervous system and initiates responses through the endocrine system.

Attached to the hypothalamus is the pituitary gland composed of the posterior pituitary and anterior pituitary.

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The posterior pituitary stores and secretes hormones that are made in the hypothalamus

The anterior pituitary makes and releases hormones under regulation of the hypothalamus

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Endocrine glands in the human brain

Spinal cord

Posterior

pituitary

Cerebellum

Pineal

gland

Anterior

pituitary

Hypothalamus

Pituitary

gland

Hypothalamus = brain

Thalamus

Cerebrum

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Posterior Pituitary Hormones

Oxytocin induces uterine contractions and the release of milk

Suckling sends a message to the hypothalamus via the nervous system to release oxytocin, which further stimulates the milk glands