Animal: Lecture 3 Flashcards
Animals have systems that..?
Perceive and respond to changes in their internal and eternal environments.
Requirements of perception and response?
Informational flow (communication)
- Chemical and or electrical signalling between cells coordinates responses at the cellular, tissue, organ, and system levels.
What are the major systems that control responses to stimuli?
The nervous and endocrine systems are the major systems that control responses to stimuli and coordinate body activities (and maintain homeostasis).
Specialization of endocrine and nervous systems?
The endocrine and nervous systems are specialized for different functions, despite both being involved with communication.
Endocrine system signalling?
Signal type = hormone
Transmission = blood and blood vessels
Speed = fast (adrenaline) or slow (puberty and most things)
Duration = short (adrenaline) or slow (puberty)
Specificity is achieved by hormone/receptor interaction. One hormone goes to cell because of the receptors, correct hormone connects with correct receptors.
Nervous system signalling?
Signal type = electrical impulse and chemical neurotransmitter
Transmission = neuron
Speed = very fast
Duration = short
Specificity is achieved by close connection of neurons and target cells (neurons, muscle, endocrine cells).
Endocrine system specialization?
The endocrine system is specialized fr coordinating gradual changes that affect the entire body.
Ex. Growth, development, reproduction, metabolic processes, and digestion. (hormone = endocrine)
Nervous system specialization?
The nervous system is specialized for directing immediate and rapid responses to the environment.
Ex. Rapid locomotion and behaviour.
What system is involved with maintaining the blood calcium levels within an appropriate range?
The endocrine system.
What was the system that was involved with the response of the octopus?
The nervous system.
What is the nervous system composed of?
Neurons and glia.
What are neurons?
Cells responsible for generating and transmitting the electrochemical impulses of the nervous system.
What are glia?
Cells that maintain homeostasis, form myelin, nourish, and provide support and protection for neurons in the central and peripheral nervous systems.
Difference between the neurons and the glia?
Neurons = basic unit of the nervous system
Glia = support cells of the nervous system
How do neurons work in communicating?
Electrical impulses are triggered at the dendrites. With sufficient stimulus to the cell body, a new electrical impulse is generated and sent down the axon. Neurotransmitter is released and crosses the synapse to bind to receptors on the postsynaptic cell.
CNS?
Brain and spinal cord
PNS?
Cranial nerves, Ganglia outside the CNS, Spinal nerves.
Ganglia?
Concentrations of neuron cell bodies.
Nerves?
Bundles of axons.
Information processing is composed of?
3 different stages:
1. Sensory input from sensor
2. Integration in brain (CNS)
3. Motor input in effector
Reflex cycle?
- Sensory intake (stimulus)
- Cell body of sensory neuron in dorsal root ganglion
- Grey matter
- one goes to interneuron, other goes to motor neuron
- Hamstring is told to relax
- Quadrilateral is told to contract
What do endocrine cells do?
Endocrine cells secrete hormones into the bloodstream, affecting target cells to regulate physiology and behaviour.
Major endocrine glands?
- Hypothalamus
- Pineal gland
- Pituitary gland
- Thyroid gland
- Parathyroid glands
- Adrenal glands
- Pancreas
- Ovaries
- Testes
- Thymus
- Heart
- Liver
- Stomach
- Kidneys
- Small intestine
Hypothalamus?
Hypothalamus is a brain region that acts as the “master regulator” of the endocrine system, primarily through the pituitary gland.
Posterior pituitary?
Made up of axons of neurosecretory cells of the hypothalamus.
Neurosecretory cell?
A neurosecretory cell is a neuron that produces a hormone and it secretes it directly into the bloodstream.
Therefore, there is a ____ between the nervous and endocrine systems?
There is a functional overlap between the nervous and endocrine systems.
Example?
Response from hypothalamus makes hormones and will send it down to posterior pituitary, which will distribute the hormones through the animal body via blood vessels.
Anterior pituitary?
The anterior pituitary is made up of endocrine cells that respond to hormones from the hypothalamus by secreting their own hormones.
Hypothalamic hormones?
Hypothalamic hormones arrive via portal vessels.
Hormones regulating endocrine glands?
Some hormones from the posterior and anterior pituitary glands regulate the function of other endocrine glands.
hierarchical organization?
Hypothalamus ~> posterior and anterior pituitary ~> other endocrine glands (thyroid, adrenals, testes, ovaries).
Endocrine or nervous: pulling hand away from hot stove?
Nervous
Endocrine or nervous: puberty?
Endocrine
Endocrine or nervous: fight or flight response?
Endocrine AND nervous
Hypothalamus?
controls the connection between the nervous and endocrine systems.
This example?
The hypothalamus affects the endocrine system without acting through the pituitary gland.
- Instead, via the nervous cells (spinal cord) to adrenal glands.
Fight or flight response…?
Stress is realized by hypothalamus ~> nerve signals reach spinal cord ~> nerve signal reaches adrenal medulla ~> adrenal medulla secretes epinephrine and norepinephrine.
Hormone effects of fight or flight response?
- Increased heart rate
- Increased breathing rate
- Increased metabolic rate
- Increased blood glucose
- Change in blood pattern
How do hormones differ?
Hormones differ in structure and solubility:
Ex. Lipid soluble are hydrophobic (cortisol or thyroxine)
Ex. Water soluble are hydrophilic (insulin in blood or epinephrine)
how do water-soluble hormones work?
They are stored in vacuoles:
- Released
- Able to easily travel through blood
- Need help of a signal receptor to get into the blood, as they are hydrophilic.
- Get to the target cell!
- Cytoplasmic response (rxns within cells)
- Gene regulation (through membrane of nucleus - hard)
How do lipid soluble hormones work?
Only made when needed:
- Pass through membrane easily
- Need transport protein to get through blood
- Easily travels through membranes
- Reaches signal receptor in the nucleus very easily.
- Almost all lipid-soluble hormones do gene regulation.
- Items made in gene regulation will be used in the cytoplasmic response.
A single hormone can have many effects?
The response of a target cell to a hormone depends on:
– The signaling pathways within the target cell
– The type of receptor on the target cell
Same receptors with different intracellular proteins?
- Epinephrine fits to B receptor on a liver cell (with glycogen deposits), leading to glycogen breaking down and glucose being released from the cell.
- Epinephrine fits to B receptor on a skeletal muscle blood vessel, causing the vessel to dilate.
Different receptors - different cellular responses?
- Epinephrine fits to B receptors of the skeletal muscle blood vessel causing the vessel to dilate.
- Epinephrine fits to a receptors of the intestinal blood vessel, causing the vessel to constrict.
Endocrine systems use what to maintain homeostasis?
Endocrine systems often use antagonistic hormones to maintain homeostasis.
What are antagonistic hormones?
- Pairs of hormones whose actions oppose each other
- Maintain a physiological parameter within an acceptable range
Ex. Insulin and glucagon are antagonistic hormones that regulate blood glucose concentration.
After eating carbohydrates?
Stimulus = blood glucose rising after eating carbs
- Beta cells of the pancreas release insulin into the blood.
- Insulin causes the body cells to take up more glucose and the liver to take up glucose and store is as glycogen
- Therefore, the blood glucose level declines.
After skipping a meal?
Stimulus = blood glucose falling after skipping a meal
- Alpha cells of the pancreas release glucagon into the blood.
- Liver breaks down glycogen and releases glucose into the blood
- Therefore, the blood glucose level rises
- HOMEOSTASIS!!!
What are these two systems an example of when together?
This is a negative feedback loop that strives to maintain homeostasis.
The receptor for “hormone X” is located in the nucleus of the target cell. Hormone X is….?
A. Water-soluble
B. Lipid-soluble
ANSWER: B
The effect of insulin on blood glucose level is an example of negative feedback?
A. True
B. False
ANSWER: A
Endocrine and nervous systems specialized?
Endocrine and nervous systems are specialized for different functions (based on differences in signalling), but there is functional overlap between the two systems.
Information flow in nervous system?
Information flow in the nervous system is based on electrical and chemical signalling within neurons, and processing occurs in three stages.
Information flow in endocrine system?
Information flow in the endocrine system is based on chemical signalling involving hormones.
Hormone effects?
Hormone effects depend on the target cell.
Antagonistic hormones?
Antagonistic hormones are commonly used to maintain homeostasis.
