Main Function: It releases hormones (chemical messengers) into the blood to signal other cells...
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Transcript of Main Function: It releases hormones (chemical messengers) into the blood to signal other cells...
• Main Function:It releases hormones (chemical messengers) into the blood to signal other cells (target cells) to behave in certain ways. It is a slow but widespread form of communication.
Endocrine glands Release hormones into the bloodstream.
Hormones are chemicals released in one part of the body that travel through the bloodstream and affect the activities of cells in other parts of the body.
Consists of:
Interaction of GlandsThe hypothalamus is located in the brain and controls the release of hormones from the pituitary gland. It is an important link between the endocrine and nervous systems.
Interaction of GlandsThe brain and glands work together to maintain homeostasis through a process called negative and positive feedback mechanisms.
Endocrine System
Pituitary Gland
Pituitary Gland
Function: It secretes nine hormones that control all other endocrine glands.
-produces human growth hormone
- Disorders: Too much growth hormone can result in a condition called gigantism. Robert
Wadlow
Endocrine System
Pituitary Gland Thyroid Gland
Thyroid Gland• Hormone: Thyroxin• Function: plays a major role in the regulation the
body’s metabolism.• Disorders:
Hyperthyroidism-too much thyroxin; fast metabolism Hypothyroidism- too little thyroxin; slow metabolism
Goiter-lack of iron in diet, no thyroxin secretion, enlargement of thyroid gland
Endocrine System
Pituitary Gland Thyroid Gland
Adrenal Glands
Adrenal Gland
• Functions: -The adrenal glands release Adrenaline in the body that helps prepare for and deal with stress.-Also regulates kidney function.
Endocrine System
Pituitary Gland Thyroid Gland
Adrenal Glands
Ovaries
Ovaries
• Functions: – Pair of reproductive organs found in
women that produce eggs.– Also secrete estrogen and
progesterone, which control ovulation and menstruation.
Endocrine System
Pituitary Gland
Pineal Gland
Thyroid Gland
Parathyroid Gland
Thymus
Adrenal Glands
Pancreas
Ovaries
Testes
Testes• Functions:
– Pair of reproductive glands that produces sperm.
– Also secrete Testosterone to give the body its masculine characteristics.
Endocrine System
Pituitary Gland
Pineal Gland
Thyroid Gland
Parathyroid Gland
Thymus
Adrenal Glands
Pancreas
Ovaries
Testes
Pancreas [Islets of Langerhans]
Insulin:
Reduces levels of glucose in the blood• conversion of glucose to glycogen •promoting glucose absorption and use by body cells
Glucagon:
Increases levels of glucose in the blood
• causes liver to convert glycogen to glucose
Negative Feedback
• Is a type of self-regulation associated with endocrine regulation
Functions like a thermostat. Only activated when there is a need. Shuts off once that need has been met.
Negative Feedback
A B
If there is too much glucose in the blood, insulin converts some of it to glycogen
Glycogen
Insulin
Glucose in the blood
If there is not enough glucose in the blood, glucagon converts some glycogen into glucose.
Glycogen
Glucagon
Glucose in the blood
Time
Glucose Concentration
Meal eaten
Insulin is produced and glucose levels fall to normal again.
Glucose levels rise after a meal.
Normal
Failure of Homeostasis:[Islets of Langerhans]
Diabetes:
Islets of Langerhans don’t make enough insulin• Glucose in blood can’t be stored as glycogen •Blood levels of glucose INCREASE
The glucose in the blood increases.
Glycogen
Insulin
Glucose in the blood
But there is no insulin to convert it into glycogen.
Glucose concentration rises to dangerous levels.
Time
Glucose Concentration
Meal eaten
Insulin is not produced so glucose levels stay high
Glucose levels rise after a meal.
Diabetic
Positive Feedback
• Enhances an existing response– Child birth
Interaction of GlandsThe feedback the brain gets is from the information it collects as the hypothalamus monitors the bloodstream. Using this information, the brain knows what hormones to start and stop releasing.
Main Function: This communication system controls and
coordinates functions throughout the body and responds to internal and
external stimuli.
Our nervous system allows us to feel pain.
Consists of: brain, spinal cord, nerves and sense organs
Sense Organs: Eyes, Skin, Ears, Nose & Tongue
A nerve is an organ containing a bundle of nerve cells called neurons.
Neurons carry electrical messages called impulses throughout the body. Picture shows hundreds of
severed neuron axons
cellbody
muscle tissue
TYPICAL MOTOR NEURON
Axondendrite
synapse
cell body
Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons.
Neurotransmitters
Synapse (gap)
The message is transferred when RECEPTORS receive neurotrans-mitters.
(pinkspheres)
Parts of a Neuron1. Cell body: contains nucleus & most of the
cytoplasm
2. Dendrites: projections that bring impulses into the neuron to the cell body.
3. Axon: long projection that carries impulses away from cell body
1
32
travels dendrite towards axon
Parts of a Neuron1. Cell body: contains nucleus & most of the
cytoplasm
2. Dendrites: projections that bring impulses into the neuron to the cell body.
3. Axon: long projection that carries impulses away from cell body
1
32
Sensory
Neuron
Interneuron
Motor Neuron
Sensory Neuron
Interneuron
Motor Neuron
Muscle Contracts
Synapse
Synapse
Synapse
Sensory Sensory NeuronNeuron
carry impulses from sense organs to
spinal cord & brain
Fun Fact:
Where can the largest cells in the world be found?
The giraffe’s sensory and motor neurons! Some
must bring impulses from the bottom of their legs
to their spinal cord several meters away!!
InterneuronInterneuron
-processes impulses in brain and spinal
cord
- connect sensory and motor neurons
Motor Motor Neurons
carry impulses from the brain & spinal cord to
muscles & glands
Axon End
Axons branching out to muscle fibers
• Nerves work together with muscles for movement. An impulse begins when one neuron is stimulated by another neuron or by the sense organs.
• The impulse travels down the axons of Sensory neurons to the brain cells called Interneurons.
• The brain will then send an impulse through motor neurons to the necessary muscle or organs, telling it to contract.
A reflex is an involuntary
response that is processed in the spinal cord not
the brain.
Reflexes protect the body before the brain knows
what is going on.
Reflex Arc
Reflex Arc
Path reflex impulse travels
Sense Receptor SensoryNeuron
SPINAL
CORD
MotorNeuronMuscle/Gland
Human Nervous System
Central Nervous System Peripheral Nervous System
[CNS] [PNS]
Brain & Spinal Cord Nerves branching from thebrain and spinal cord
brain
Spinal Cord
Cerebellum
Cerebrum
Medulla Oblongata
Consists of: Brain and Spinal Cord
Cerebrum Voluntary or conscious activities of the body-learning, judgment
Cerebellum Coordinates and balances the actions of the muscles
Medulla Oblongata
(Brain Stem)
Controls involuntary actions like blood pressure, heart rate, breathing, and swallowing
Spinal Cord
The main communications link between the brain and the rest of
the body
Consists of: Sensory division
and Motor division
-includes all sensory neurons, motor neurons,
and sense organs
Subdivisions of PNSSomatic Nervous System:
• voluntary control• responsible for conscious body movement
Autonomic Nervous System:
• no voluntary control• serve internal organs• involved with: heart rate
blood flow breathing movements digestive system gland secretions
Autonomic Nervous System:
Sympathetic: “fight or flight”speed up body functions
Parasympathetic:slow down body functions
Concept Map
which consists of
is divided into
that make up
which is divided into
The Nervous System
Sensory nerves
Motor nerves
Autonomic nervous system
Somatic nervous system
Central nervous system
Peripheral nervous system
Sympathetic nervous system
Parasympathetic nervous system
Nervous vs. Endocrine System
Similarities:
• both involved with maintaining homeostasis• both secrete chemicals
Endocrine System: hormones Nervous System: neurotransmitter
Differences:
• NS response is much faster than ES response• ES response lasts longer than NS response• Nerve impulse transmitted by neuron, hormones transported by the blood