Lecture 9 Flashcards
Whats makes up the CNS
- Brain
- Spinal cord
Whats part of the PNS
- Somatic nervous system (conscious actions)
- Autonomic nervous system (unconscious actions)
What makes up the CCN
- CNS
- PNS
- Endocrine system
- Local support and defence system
Explain Alzheimers in comparison to the nervous system
- Lots of neurons going to the brain are lost
- Acetylcholine can be reduced by up to 90%
- Changing in signalling molecules have serious impact on health
What is the input and output of the CNS
Sensory input and motar output
Explain sensory input
Response to external stimuli
Explain the 2 types of sensory input
1) Inputs from internal organs (signalling that you’re feeling full)
2) Input from sensory receptors on skin and joints
Explain motor output
Actions signalled by the CNS
What type(s) of motor output does the SNS direct
Directs voluntary movements
What type(s) of motor output does the ANS direct
Regulates bodily activities such as HR and BR
What are the roles of parasynthetic vs synthetic nervous system on motor output
Parasympathetic nervous system: Governs bodily activities during restful states
Sympathetic nervous system: Prepares body for emergencies
What are the 5 major cell types in adult CNS
1) Neurons
2) Oligodendrocytes (CNS) and Schwann cells (PNS)
3) Astrocytes
4) Microglia
5) Ependymal Cells
What is the role of neurons
Transmit electrical signals
Can neurons be be excitatory or inhibitory
Yes
Explain dendrites, cell body, axon, and axon endings of neurons
- Dendrites: receive info from other neuron or environment
- Cell body: controls cells metabolic activity, generates input from other neurons
- Axon: Conducts nerve impulse away from cell body
- Axon ending: release chemicals called neurotransmitters that affect of the nearby neuron and effector
Where is action potential regenerated in neurons
Action potential regenerated in dendrite vessels
Characteristics of unmyelinated neurons
- Unmyelinated neurons do not have myelin sheath
— Neurons travel 0.5 to 2m/sec
— Very few of these
Characteristics of myelinated neurons
- Myelinated have myelin sheath
— Neurons travel 6m to 120m/sec
— Quicker nerves signaling
MS connection to myelin sheeth
In Multiple sclerosis, there is a disturbance of the myelin sheath, due to an autoimmune disease
Do all neurotransmitters share a general site?
No, there’s very specific sites for neurotransmitters in neurons
Neurons release one type of neurotransmitter at given pre-synaptic neuron
What is net response of neurons based on
Net response based on overall (summation) effect on all imputes
What is needed for generation of action potential
1) More excitatory than inhibitory neurons
2) Action potential threshold met
How does the body maintain homeostasis with neurons
Body will release excitatory or inhibitory neurons to maintain homeostasis
Examples of the body maintain homeostasis with neurons
Acetylcholine in excitatory - increase HR
Epinephrine in inhibitory - decrease HR
If HR is too high, epinephrine will be release to lower heart rate
How does the body remodel neural networks at 10
- New neural synapses - can enhance memory and ability to learn
- Pruning away unused synapsis
What causes bad behaviour in toddlers
Turnover in neural networks
What is the role of Oligodendrocytes (CNS) and Schwann cells (PNS)
Responsible for producing myelin
Compare Oligodendrocytes (CNS) and Schwann cells (PNS)
Oligodendrocytes span multiple axons having an affect on multiple neurons
Schwann cells do not span multiple axons, only support one axon
Shape of astrocytes
Stellate (Starlike) cells
What are astrocytes used for
Important for communication
What are astrocytes abundant in
Very abundant in neurons
5 functions of astrocytes
1) Cordinae overall function of blood brian barrier (BBB) and provide nutrients to feed neurons
2) Coordinate function of the ventrice epithelium (brain network)
3) Coordinate function at nodes of Ranvier
4) Participate in.form tripartite synapse with neurons
5) Serves as “superhubs” for neutral networks via syncytium formation and calcium signaling ( astrocyte cells)
Define microglia
Macrophage-like immune cells
Role of ependymal cells
Lines ventricles to form a barrier, produces cerebrospinal fluid
What is the Brain blood barrier (BBB)
Has very tight control over what gets through the brain - neurons are meant to be long lived and typically do not regenerate
Good protection against most bacteria and toxins
What gets through the BBB
Small lipid soluble compounds (essential fatty acids)
Caffeine and alcohol
Glucose gets through with specific glucose transporter GLUT1 (not insulin sensitive)
Issue with small molecules traveling brain molecule is for drugs in the pharmaceutical industry to be able to make drugs small enough to cross to brain
