Ch 1 Flashcards
homeostasis
constancy of the internal environment that is the condition for a free and independent life
–> environmental factors (pH), materials (nutrients/water), and internal secretions (hormones)
homeostasis: negative feedback
Response opposes or removes the signal
Can restore normal state, but cannot prevent initial signal
homeostasis: positive feedback
response increases the initiating signal
feedback chain
signal –> sensor –> integrating center –> effector (pos/neg feedback) –> homeostasis
Intrinsic regulation
within organ (ex. dilation/constriction of vessels)
extrinsic regulation
regulation by nervous/endocrine (hormone) systems (ex. nerve fibers innervate organs, hormone secretion)
Blood Pressure Regulation
- Blood pressure falls (stimulus)
- Blood pressure receptors respond (sensor)
- -> Integrating Center: sensory/motor nerve fibers and medulla oblongata - Heart rate increases (effector)
- Rise in blood pressure (neg feedback response)
Blood Glucose Regulation (eating)
- eating
- rise in blood glucose
- pancreatic cells release insulin –> increase cellular uptake of glucose
- decrease in blood glucose
Blood Glucose Regulation (fasting)
- fasting
- decrease in blood glucose
- pancreatic cells decrease release of insulin and increase release of glucagon –> decrease of cellular uptake of glucose and increase of glucose released into blood by liver
- increase in blood glucose
Antagonistic Effectors
increased activity of one effector is accompanied by decreasing activity of antagonistic effector.
• Refined control
Primary Tissues
- Muscle: skeletal, smooth, cardiac; specialized for contraction (in glands/vasculature)
- Nervous: neurons and support cells (conduct impulses/send signals)
- Epithelial Tissue
- Connective tissue: blood, adipose (fat), bone, cartilage. (embedded in a matrix)
organ
two or more primary tissues
organ system
organs grouped by common function
Skeletal Muscle
- voluntary
- striated (can lift more weight)
- multi nucleated, pushed to edge
- arranged parallel (each myofiber can by controlled individually)
Cardiac Muscle
- involuntary
- striated
- intercalated discs: contact between adjacent cells, couple cells mechanically and electrically (work as a group)
- multi nucleated, larger than in skeletal
Smooth Muscle
- involuntary
- no striations
- random arrangement
- large nuclei
- ex. digestive tract, blood vessels
Nervous Tissue
- Neurons: generate and conduct electrical signals
- Cell Body
- Dendrites: receive info, increase SA
- Axons: conduct impulses
- Neuroglial: support cells, allow neurons to do job
Epithelial Tissue: Structure
- 1+ layers of epithelial cells
- basement membrane (foundation, easier to repair)
- controls what enters/leaves internal environment
- Two types
1. Sheets of cells lining body surfaces 2. Secretory epithelia
Structural Classification
Layering – Simple or stratified Shapes – Squamous, cuboidal, columnar Function – Exchange, transporting, ciliated, protective, secretory
Simple Epithelial Tissue
Squamous -Flattened, Diffusion, Filtrations Cuboidal -Square, Excretion, Secretion, Absorption Columnar -Rectangular, Secretion, Absorption
Exocrine and Endocrine Glands
Exocrine (outside): secrete something outside to the external environment
–> Sweat Glands, Reproductive
Endocrine (inside): secrete something into internal environment (into circulation)
–> Hypothalamus, Thyroid, Adrenal
Connective Tissues: Structure
-lots of extracellular material
1. Ground Substance: Highly variable, Matrix fibers (collagen, elastin, fibronectin) –> extracellular: cells embedded within
2. Cells
-Fixed
•Blasts (build), clasts (breakdown), and cytes (neither)
– Mobile (defense)
3. Connective Tissue, Cartilage, Bone, Blood
**know types
