Lecture 22. Nervous Regulation of Physiological Function Flashcards
What does homeostasis in animals rely heavily on ?
Negative feedback
What is negative feedback ?
Helps to return a variable to a normal range
What are some things that rely on negative feedback ?
Temperature regulation, blood glucose regulation
What is the function of positive feedback ?
Amplifies a stimulus in animals in a small number of functions
What may you see positive feedback in ?
Childbirth, blood clotting, electrical impulses in nerves
What is feedforward ?
Anticipatory responses to expected change
What are some examples of feedforward ?
Increased heart rate in anticipation of exercise, increased secretion of insulin before food is digested to yield glucose, stimulation of gastric secretions due to thought/smell of food
What does external environment contain ?
- Temperature
- 02, CO2, water, food
- Light
- Noxious stimuli/predators
What does the internal environment contain ?
- Composition of body fluids
- Temperature
- Metabolites
- Blood pressure
- 02 and CO2 in tissues
What are the fluid compartments of the human body ?
- Total body water
- Intracellular fluid
- Extracellular fluid
- Plasma
- Interstitial fluid
What is the volume of the total body water ?
42 L
What is the volume of intracellular fluid ?
28L
What is the volume of extracellular fluid ?
14L
What is the volume of plasma ?
3L
What is the volume of interstitial fluid ?
11L
What is physiological function regulated by ?
- Nervous system
2. Endocrine system
What is the nervous system ?
A network of specialised cells (neurons) that transmit signals along dedicated pathways
What are some features of the nervous system ?
- Hard wired
- Fast acting
- Electrical and chemical signaling
- Local cellular responses
- Rapid response by target cell
What is the function of endocrine system >
Chemical signaling by hormones
What are some features of endocrine system ?
- Hormones transported in blood
- Slower acting
- Chemical signaling often involves changes in gene expression
- Slower and often long lasting responses of target cells
What are four examples of interaction an cooperation?
- Some nerves innervate endocrine glands, eg. adrenal glands
- Hypothalamus and pituitary are brain regions that regulate endocrine function
- Blood pressure is regulated by nerves acting on the heart and blood vessels and by hormones acting on kidneys to regulate blood volume
- Glial cells in the nervous system play an important role in nervous function
What derives from efferent neurons ?
- Autonomic nervous system
2. Motor system
What derives from autonomic nervous system ?
- Sympathetic division
- Parasympathetic division
- Enteric nervous system
What does the autonomic nervous system control ?
Control of smooth muscles, cardiac muscles, glands
What is found in the forebrain ?
- Cerebrum
- Thalamus
- Hypothalamus
What is found in the hindbrain ?
- Pons
- Medulla oblongata
- Cerebellum
What is the brainstem ?
Consists of the midbrain, the pons and the medulla oblongata
What is the function of the midbrain ?
Receives and integrates sensory information and sends it to specific regions of the brain
What do the pons and medulla do ?
Transfer information between the peripheral nervous system and the midbrain and forebrain
What is the function of the medulla ?
Controls several basic functions such as breathing, heart and blood vessel activity, swallowing, vomiting and digestion
What is the function of the cerebellum ?
Coordinates movement and balance and helps in learning and remembering motor skills
What does the diencephalon do ?
Give rise to the thalamus, hypothalamus and epithalamus
What does the hypothalamus do ?
Constitute a control center that includes the body thermostat and central biological clock - homeostasis
What is the cerebrum ?
Controls skeletal muscle contraction and is the center for learning, emotion, memory and perception
What is the outer layer of the cerebrum called ?
Cerebral cortex
What is the cerebral cortex vital for ?
Perception, voluntary movement and learning
What is the corpus callosum ?
A thick band of axons
What does the corpus callosum enable ?
The right and left cerebral cortices to communicate
What does the motor cortex do ?
Control of skeletal muscle
What does the prefrontal cortex do ?
Decision making and planning
What does broca’s area do ?
Form speech
What does the auditory cortex do ?
Hearing
What does wernicke’s area do ?
Comprehending language
What does the visual cortex do ?
Process visual stimuli and pattern recognition
What does the visual association cortex do ?
Combining images and object recognition
What does the sensory association cortex do ?
Integration of sensory information
What does the somatosensory cortex do ?
Sense of touch
What is found in the parietal lobe ?
- Somatosensory cortex
2. Sensory association cortex
What is found in the frontal lobe ?
- Motor cortex
- Prefrontal cortex
- Broca’s area
What is found in the temporal lobe ?
- Auditory lobe
2. Wernicke;s area
What is found in the occipital lobe ?
- Visual cortex
2. Visual association cortex
How many cranial nerves are there ?
12
What are the cranial nerves
I. Olfactory nerve II. Optic nerve III. Oculomotor nerve IV. Trochlear nerve V. Trigeminal nerve VI. Abducens nerve VII. Facial nerve VIII. Vestibulocochlear nerve IX. Glossopharyngeal nerve X. Vagus nerve XI. Accessory nerve XII. Hypoglossal nerve
What is the function of the olfactory nerve
The olfactory nerve transmits sensory information to your brain regarding smells that you encounter
What is the function of the optic nerve ?
The optic nerve is the sensory nerve that involves vision.
What is the function of the oculomotor nerve ?
The oculomotor nerve has two different motor functions: muscle function and pupil response.
What is the function of the trochlear nerve
The trochlear nerve controls your superior oblique muscle. This is the muscle that’s responsible for downward, outward, and inward eye movements.
What is the function of the trigeminal nerve ?
Has three divisions: opthalmic, maxillary, mandibular
What is the function of the abducens nerve ?
The abducens nerve controls another muscle that’s associated with eye movement, called the lateral rectus muscle. This muscle is involved in outward eye movement
What is the function of the vestibulocochlear nerve ?
vestibulocochlear nerve has sensory functions involving hearing and balance.
What is the function of the accessory nerve ?
Controls muscles in neck
What is the function of the hypoglossal nerve ?
Controls muscles in tongue
What is the visceral afferent ?
Incoming pathway for information from internal viscera
What do sensory afferents do ?
Somatic sensation: arises from body surface and proprioception
What do sensory afferents of the PNS do ?
Send information from internal and external environments to CNS
What are the two efferent components of the PNS ?
- Motor system
2. Autonomic nervous system
What does the motor system do ?
Carries signals to skeletal muscles and is mainly voluntary
What does the autonomic nervous system do ?
Regulates smooth and cardiac muscles and is generally involuntary
What does the enteric nervous system do ?
Exerts direct control over the digestive tract, pancreas and gallbladder
What does the sympathetic division do ?
Regulates arousal and energy generation
What does the parasympathetic division do ?
Has antagonistic effects on target organs and promotes calming and a return to rest and digest functions
Where do the autonomic nervous system extend from ?
CNS to an innervated organ
What are the two neuron chains from autonomic nerve pathway ?
- Preganglionic fiber
2. Postganglionic fiber
What is a ganglion ?
A collection of cell bodies in the PNS
What is the name for a ganglion in the CNS ?
Nucleus
What gland only receives a sympathetic innervation ?
Sweat
What does dual innervation of organs by both branches of the ANS allow ?
Precise control over organ activity
Functions of parasympathetic division ?
Constricts pupil of eye Stimulates salivary gland secretion Constricts bronchi in lungs Slows heart Stimulates activity of stomach and intestines Stimulates activity of pancreas Stimulates gallbladder Emptying of bladder Promotes erection of genitalia
Functions of the sympathetic division ?
Dilates pupil of eye Inhibits salivary gland secretion Sympathetic ganglia Relaxes bronchi in lungs Accelerates heart Inhibits activity of stomach and intestines Inhibits activity of pancreas Stimulates glucose, release from liber, inhibits gallbladder Stimulates adrenal medulla Inhibits emptying of bladder Promotes ejaculation an vaginal contractions