Midterm 4 Flashcards
(54 cards)
Cells are organized into
Tissues, organs, and organ systems
Tissue is
A group of similar cells that perform a certain function
An organ is
A structure in the body that has a specific function
An organ system is
Responsible for a particular body function
Homeostasis
The maintenance of relatively stable internal environment. Characteristic of all living organisms
Examples:
- body temperature
- oxygen levels of blood
- amount of water in the body
- concentration of ions inside and outside cells
- blood pH
The nervous system consists of two parts:
- Central nervous system: brain and spinal cord
- Peripheral nervous system: all the other nerves in the body
The nervous system consists of two types of cells:
Neurons: receive and transmit electrical signals
Glial cells: support, insulate, and protect neurons
A typical neuron consists of
- DENDRITES that receive info from other neurons or cells
- CELL BODY that contains the neurons nucleus and organelles
- AXON that transmits info to other neurons or cells
Myelin
A myelin sheath allows an action potential to be transmitted more quickly down an axon
What does the myelin sheath consist of?
Glial cells wrapped around and around an axon.
There are periodic gaps in the sheath and the action potential jumps down the axon from one gap to the next
What happens in electrical synapses?
Ions move directly from a neuron to a target cell through tiny channels called gap junctions
What does electrical synapses transmit and where are they found?
Transmit action potentials rapidly and are found in places such as heart muscle
What does the brainstem controls?
Involuntary activities (heartbeat, respiration, and digestion)
What does the cerebellum control?
Balance, posture, coordination, and fine movements
Amygdala
An important target of the central stream for object recognition
Hyperactivity is the amygdala
PTSD
Low activity of the amygdala
Disinhibition; hypersexuality
Rods
- sensitive to light
- responsible for vision in dim light
- cannot discriminate color
Cones
- Detect color
- diff cones detect green, red, and blue light
- ability to see fine details
Smell and Taste
These senses rely on chemoreception - a process in which chemicals bind to receptors in the cell membrane of chemosensory cells.
The binding opens ion channels and initiates action potentials.
How many different kinds of chemosensory cells do humans have for smells?
1,000
Triggered in diff combos, can detect 10,000 odors
Where are taste cells found?
Taste buds
Five basic tastes?
Sweet Salty Sour Bitter Umami
What other senses affect touch?
Pressure, temperature, pain
