Lecture 22 Flashcards
What are the two major control centres of human body
Nervous and endocrine
What does the nervous system do
Receives and interprets stimuli and transmits impulses to organs
Brain contains many of the
Homeostatic control centres
3 basic functions of nervous system
- Sensing
- Integrating
- Controlling
Sensing function
Receptors of body detect stimuli and send information to CNS
Integrating function
Sensory info received and processed, complex integration involves connecting sensory info with memories and emotions
Controlling function
Motor neurons send info to diff effectors (muscle or glands) to produce response likely conductive to survival
Neurons are
Very large cells capable of receiving/sending electrical signals bet two locations within body
Neuroglial cells
Smaller than neurons, remove waste, assist neurons in receiving/sending electrical signals
Peripheral nervous system (PNS)
Consists of all nerves, ganglia (grp of nerves) and sensory receptors
Central nervous system (CNS)
Consists of spinal cord and brain
CNS is in charge of
- Receiving, integrating, processing info of sensory division
- Sending command signals to effectors through motor division (somatic/autonomic)
Homeostatic control centers of body in CNS receives info and evaluates to
Determine whether a response should be sent to a specific effector
A homeostatic control center within CNS is
Grp of neurons that receive/process sensory info detected from specific receptors in body sent via PNS
When info received by homeostatic cc is out of range,
Control center send out signal to effector
Forebrain components
- Cerebrum
- Thalamus
- Hypothalamus
Hindbrain components (brain stem)
- Pons
- Medulla
- Cerebellum
Forebrain contains the control centers for
- Thermoregulation
- Emotions
- Conscious perception
- Voluntary motor control
- Language
- Highest-level processing (ethics, abstract)
Hypothalamus regulates
- Bp
- HR
- RR
- Digestion
- Body temp
Hypothalamus coordinates nervous and endocrine through
Its connection with pituitary gland
Midbrain
Only structure in midbrain
Superior to pons, inferior to thalamus
Plays crucial role in processing visual and auditory signals
Medulla and pons contain control center for
Basic homeostatic mechanisms (ex heart rate and breathing rate)
Cerebellum crucial for
- Execution of fine mvmts
- Maintaining balance and posture
- General coordination of mvmts
Why is spinal cord in CNS
Bc also in charge of processing and integrating some info (ex reflexes)
Nerves consist of
Bundles of neurons cells packaged in connective tissue
Each neuron can send info from
- Sensory receptor to CNS
- From CNS to effector
PNS does not process info or “make decisions”, so it is like
Network of electrical highways that lead to and from organs of CNS
In what direction do neurons send electrical signals
One direction (always the same)
Types of neurons
- From receptor to CNS: sensory neuron
- From CNS to effector: motor neuron
Nerve structure
Bundle of bundles of neuron fibers (neuron’s axon which is longest extension of neuron cell)
Nerves important for respiratory system
Phrenic and thoracic nerves
Motor neurons divisions
- Somatic nervous syst (to skeletal muscles)
- Autonomic nervous syst (to smooth. Cardiac muscles, glands and adipose)
Two subsystems of autonomic nervous system
- Sympathetic
- Parasympathetic
The effectors that parasympathetic/sympathetic systems control are
All the same (with few exceptions)
Ex: cardiac muscle slows or increase depending in which system)
Sympathetic NS =
Fight or flight (stressful situations)
Effectors receiving sympathetic stimulation include
All involuntary effectors
Ex smooth/cardiac muscles, various glands
Theses responses get body on alert
Sympathetic NS called fight or flight bc
In past, threats were primarily physical rather than psychological
Sympathetic response: inhibition of digestive system
Smooth muscles signaled to relax
Sympathetic response: cardiac output
Cardiac muscle signaled to contract at higher frequency
Smooth muscle in bv cause vasoconstriction
Sympathetic response: bronchodilation
Smooth muscle in bronchiolar walls relax to decrease airway resistance
Sympathetic response: inhibition of urination
Smooth muscle in bladder relaxed
Sympathetic response: hormonal stress response
Stimulates secretion of adrenaline (epinephrine) into blood
Specific sympathetic responses
- Inhibition of digestive system
- Increased cardiac output
- Bronchodilator
- Inhibition of urination
- Trigger of hormonal stress response
Parasympathetic specific responses
- Increase in digestive activity (more peristalsis)
- Decrease in cardiac output (decreased HR and vasodilation)
- Bronchoconstriction
- Promotion of urination (if bladder partially full)
Parasympathetic system =
Rest and digest/relaxation
Sensory (afferent) division consists of neurons that
Conduct electrical impulses from receptors to organs of CNS
