Midterm #1 Flashcards
Negative Feedback
the response counteracts the stimulus
Positive Feedback
the response reinforces the stimulus, sending variable farther from the setpoint
3 main body cavities
Cranial Cavity - Brain Thoracic Cavity - Lungs & Heart Abdominopelvic Cavity - Gastrointestenal tract, liver, kidneys, spleen & female reproductive tract
Extracellular Fluid ECF
1/3 total body fluid 17 litres - Interstitial fluid 13 litres - Plasma 3 litres - Transcellular fluid 1 litre Mostly Na+, Cl-
Intracellular Fluid ICF
2/3 total body fluid
25 litres
- fluid inside cells
Most K+
Homeostasis
To maintain nearly constant conditions in the internal environment
- Bodily functions
- Chemical compositions
- ECF is often called the internal environment
4 basic steps in feedback mechanism
Stimulus -> Receptor -> Control Centre -> Effector
- Senses parameter using sensor/receptor (needs stimulus)
- Compares the parameter to the set-point (normal range of function)
- Output signal to control centre
- Output signal from control centre then activates the effector to bring the parameter closer to the set-point
Four Main Cell types in the epidermis
Keratinocytes, melanocytes, Intraepidermal macrophages, tactile epithelial cells (Merkel cells)
Keratinization
process in which newly formed keratinocytes push from the stratum basale toward the outer layer of the epidermis, more keratin is accumulated
Keratinocytes
- 90% of epidermal cells
- Produce keratin
- Protect underlying tissues
- Also produce lamellar granules (water repellent sealant function)
Melanocytes
- Produce pigment melanin
- Melanin granules protect keratinocytes
- Suseptable to UV damage
Intraepidermal Macrophage
- Immune cells
- Recognize invading microbes and destroy
Tactile epithelial cell (Merkel Cells)
- function is to detect touch sensations
Freckles
accumulation of melanin in patches and so are age spots
Mole
benign localization overgrowth of melanocytes
Albinism
a condition that the melanocytes of an individual fail to produce melanin
Vitiligo
(skin with irregular white spots) is a condition that an individual with partial or complete loss of melanocytes from patches of skin
Two types of skin wound healing
epidermal & deep wounds
Four phases of deep wound healing
- Inflammatory Phase
- Migratory Phase
- Proliferative Phase
- Maturation Phase
Inflammatory Phase
- Blood clot
- elimination of microbes
Migratory Phase
- Clot becomes a scab
- 2-3 days after, fibroblasts migrate to injury
- Fibroblasts produce structural molecules (scar tissue)
- Angiogenesis (regrow of blood vessels
Proliferative Phase
- Extensive growth of epithelial cells beneath scab
Maturation Phase
- Degration of the scab
- Epidermis thickness restored to normal thickness
Integral membrane proteins
Tightly attached to the membrane
- Lipid anchored proteins
- Transmembrane proteins (channel)
Peripheral membrane proteins
Loosely attached to the membrane (by the polar head or other proteins)
Vesicular Transport
For macromolecules that are too large for protein mediated transport (channel) systems
Epithelial Transport
moving substances across 2 membranes
Apical Membrane
Surface of the singing facing the lumen of an organ
Basolateral Membrane
Surface of the lining facing the extracellular fluid
Paracellular Transport
Through junctions between adjacent cells
Transcellular Transport
Through both the apical and basolateral membrane with the help of carrier proteins (channels) or by means of transcytosis
Transcytosis
Combination of endocytosis, vesicular transport across the cytoplasmic space and exocytosis
Allow the transport of macromolecules, remain intact.
Depolarization
Membrane potential becomes less -ve than the resting membrane potential
Repolarization
Membrane potential return back to
the resting membrane potential
Hyperpolarization
Membrane potential becomes more –ve than the resting membrane potential
On Occasion Our Trusty Truck Acts Funny Very Good Vehicle Anyway
Mnemonic for 12 cranial nerves
Some Say Marry Money. But My Brother Says Big Brains Matter More
Mnemonic for remembering which 12 cranial nerves are Sensory, Motor or Both
Dendrites
Are thin branches (processes) of a neuron that receive incoming information from neighboring cell
Axon
transmit electrical signals from the soma of a neuron to its presynaptic axon terminals where information is transformed from electrical to chemical and passes onto the neighboring cells
Axonal Transport
transporting vesicles and mitochondria, produced by the nucleus within the soma, to the axon terminal and return the synaptic vesicle from the axon terminal back to soma for recycling
Astrocytes
(CNS)
Provide neutrons with substrate for ATP production
Maintaining an appropriate environment for the generation of nerve impulses
Oligodendrocytes
Myelin forming glial cells in CNS
Microglia
Function as phagocytes and remove cellular debris (CNS)
Ependymal cells
(CNS) Lining of the ventricular system of the brain and central canal of the spinal cord.
Satellite cells
(PNS) Form supportive capsules around the cell bodies of the neurons in PNS which is known as ganglion
- Regulate the exchanges of materials between soma and interstitial fluid
Ganglion
a cluster of nerve cell (mainly soma and dendrites) appear as a swelling structure along a nerve
Schwann Cells
(PNS) Form Myelin sheath around axons
* A single PNS axon may have as manny as 500 different Schwann cells along its length
Myelination
Myelin sheath insulates the axon of a neuron
- Increases speed and fidelity of nerve conduction
Synapse
The region where an axon terminal communicates with its postsynaptic target cell
Electrical synapse
Structural connection known as gap junction that forms a conductive link containing connexon channels
- Each gap junction contains hundred or so connexions
- Low electrical resistance for minimal delay
Chemical Synapse
Use neurotransmitters to provide electrical continuity between adjacent cellsMajority of the neural synapses are the chemical synapses
Neurocrine
Chemical signal in a form of neurotransmitter secreted by the neutron
Ganglia
Groups of neuronal cell bodies outside the CNS
Plexuses
Branching network of axons outside the CNS
Dorsal root
carries sensory (afferent) information to CNS
IN
Ventral root
carries motor (efferent) information to muscles and glands
OUT
Spinal Cord white matter
Can be divided into columns which are the tracts of axons that transfer info up and down the spinal cord
Ascending tracts
carry info up to the brain
Descending tracts
carry mostly efferent (motor) info from the brain to the spinal cord