Body Fluids
Chapter 45
Hormones and the Endocrine System
PowerPoint Lectures for Biology, Seventh Edition
Lectures by Ching-wei Luo
Hormone (from the Greek horman, to excite)
• Overview: The Body’s Long-Distance Regulators • Hormone definition: a chemical signal secreted into the circulatory system and communicates regulatory messages within the body
• Hormones may reach all parts of the body
But only certain types of cells (target cells) are equipped to respond Q
Two systems act individually and together in regulating an animal’s physiology
Endocrine system
Constituted by hormone–secreting cells and glands Secretes hormones that coordinate slower but longer-acting responses to stimuli “ductless”
升糖激素
Two systems act individually and together in regulating an animal’s physiology
Nervous system
Conveys high-speed electrical signals along specialized cells called neurons rapid messages control the movement of body parts
vesicle
Secrete signal molecules
Endocrine cell
Neuron
neurosecretory cells: release neurohormones into the blood
Pathway Stimulus Example Low blood glucose Receptor protein Pancreas secretes glucagon ( ) Endocrine cell Blood v essel Pathway Stimulus Example Suckling Pathway Stimulus Example Hy pothalamic neurohormone released in response to neural and hormonal signals
Sensory neuron
Hypothalamus / posterior pituitar y
Sensory neuron
Hypothalamus
Neurosecretory cell Posterior pituitary secretes oxytocin ( )
Neurosecretory cell Hy pothalamus Blood v essel secretes prolactinreleasing hormone ( )
Blood v essel Target effectors Liv er
Response
Glycogen breakdown, glucose release into blood
Target effectors
Smooth muscle in breast Endocrine cell
Anterior pituitary secretes prolactin ( )
(a)
Simple endocrine pathway
(b)
Response
Milk release
Blood v essel
Homeostasis Feedback •negative •positive
Simple neurohormone pathway
Target effectors Mammary glands
Milk
Hormones and the Endocrine System
PowerPoint Lectures for Biology, Seventh Edition
Lectures by Ching-wei Luo
Hormone (from the Greek horman, to excite)
• Overview: The Body’s Long-Distance Regulators • Hormone definition: a chemical signal secreted into the circulatory system and communicates regulatory messages within the body
• Hormones may reach all parts of the body
But only certain types of cells (target cells) are equipped to respond Q
Two systems act individually and together in regulating an animal’s physiology
Endocrine system
Constituted by hormone–secreting cells and glands Secretes hormones that coordinate slower but longer-acting responses to stimuli “ductless”
升糖激素
Two systems act individually and together in regulating an animal’s physiology
Nervous system
Conveys high-speed electrical signals along specialized cells called neurons rapid messages control the movement of body parts
vesicle
Secrete signal molecules
Endocrine cell
Neuron
neurosecretory cells: release neurohormones into the blood
Pathway Stimulus Example Low blood glucose Receptor protein Pancreas secretes glucagon ( ) Endocrine cell Blood v essel Pathway Stimulus Example Suckling Pathway Stimulus Example Hy pothalamic neurohormone released in response to neural and hormonal signals
Sensory neuron
Hypothalamus / posterior pituitar y
Sensory neuron
Hypothalamus
Neurosecretory cell Posterior pituitary secretes oxytocin ( )
Neurosecretory cell Hy pothalamus Blood v essel secretes prolactinreleasing hormone ( )
Blood v essel Target effectors Liv er
Response
Glycogen breakdown, glucose release into blood
Target effectors
Smooth muscle in breast Endocrine cell
Anterior pituitary secretes prolactin ( )
(a)
Simple endocrine pathway
(b)
Response
Milk release
Blood v essel
Homeostasis Feedback •negative •positive
Simple neurohormone pathway
Target effectors Mammary glands
Milk