Homeostasis and Negative feedback (L2-3)

Purpose of the Microvilli

Projections that increase the surface area for obsorption

Purpose of the Centrioles

A feature that aids in Cell Replication (animal cell only)

Purpose of the Rough Endoplasmic Reticulum (RER)

an organelle that has ribosomes that help make proteins

Purpose of the of the Nucleolus

Helps make RNA

Purpose of the Nucleus

Stores DNA

Purpose of the Cytoplasm

The medium that allows for reactions to occur (such as glycolosis)

Purpose of the Golgi Aparatus

“processing and packing”
Protein modification and export

Purpose of the Plasma Membrane

Manages transport in/out of the cell and helps with signalling

Purpose of the Lysosome

Degrades and breaks down proteins and organelle via enzymes and low pH

Purpose of the Mitochondria

Produces ATP

Purpose of the Ribosomes

Makes Protein

Purpose of the Vacuole

Gets rid of waste and acts as storage

Purpose of the Smooth Endoplasmic Reticulum (SER)

Lipid Production and cell detox

the level of organization (8)

Atom
Molecule
Organelle
Cell
Tissue
Organ
System
Organism

Disease is TYPICALLY at the ____ level
Unless its blood, in which its at the ______ level

tissue
system

T/F
Systems have multiple types of tissue

True

What are the FOUR (4) PRIMARY types of tissue?
Include examples that fall under each one

Muscle (contraction):
- Skeletal Muscle Tissue
- Cardiac (heart) Muscle Tissue
- Smooth Muscle Tissue

Nervous (Signal):
- Central Nervous Tissue
- Peripheral Nervous Tissue

Epithelial (Xchange):
- Epithelial sheets (form boundaries)
- Glands (secretion)

Connective (Structural Support):
- Tendons
- Bones / Skeleton
- Blood

What is SKELETAL MUSCLE

the muscle that is connected to the skeleton

Parts of the Body System: Circulatory System

Heart
Blood Vessels
Blood

Parts of the Body System: Digestive System

Mouth
Esophagus
Stomach
Intestines
Related Organs

Parts of the Body System: Respiratory System

Lungs and Major Airways

Parts of the Body System: Urinary System

Kidneys and Associated Structures

Parts of the Body System: Skeletal System

Bones and Joints

Parts of the Body System: Immune System

White Blood Cells
Lymphoid Organs

Parts of the Body System: Muscular System

Skeletal Muscles

Parts of the Body System: Integumentary System

Skin and Related Structures

Parts of the Body System: Nervous System

Brain
Spinal Cord
Nerves
Sense Organs

Parts of the Body System: Endocrine System

ALL Hormone-Secreting Glands

Parts of the Body System: Reproductive System

Male and Female gonads and related organs

Define Homeostasis

Homeostasis is the maintenance of a dynamic steady state in the internal environment.

Is homeostasis a set point or range

range

Examples of variables that are maintained homeostatically (8):

– Concentration of nutrients
– Partial pressure of O 2 and CO 2
– Concentration of metabolic waste products
– Blood pH
– Blood osmolarity
– Concentration of Na+, K+ and other electrolytes
– Blood volume and pressure
– Body temperature

Cells exchange materials from the _______ fluid, with the _______fluid and blood/plasma

intracellular (inside)
intercellular (outside)

Homeostasis needs

body systems

generalized steps to restoring homeostasis

detect deviation (sense)
Integrate/share the info (control)
Respond and restore (effect)

Negative feedback system and its parts

A system that runs to restore homeostasis

effector // sensor //control system

homeostatic control system

an interconnected network of body components that work together to maintain a given factor relatively constant.

Negetive Feedback remidates ________ _________

UNWANTED CHANGE

Afferent Signal

Sends the information from the sensor to the control center / integrator

Afferent = away

Efferent Signal

Used to send information from the control center to the effectors (cells/organs) that need to perform an action to help restore homeostasis

efferent = effective solution

can negative feedback work at multiple levels

yes

Pathophysiology

abnormal functioning of the body associated with disease

What happens when homeostasis deviation is too severe

death

Examples of pathophysiology

cancer
sickle cell
ahltzimer’s

Describe Intrinsic Control System

Local
Control systems are built into the system

Describe Extrinsic Control Systems

The control system is EXTERNAL to the system and causes coord’d regulation of organs

T/F
Homeostasis is regulated by Only extrinsic control systems

FALSE
It is controlled by both In/Extrinsic

examples of Intrinsic Control systems

Working Out specific muscles

why:
→ working out causes blood cells to form CO2, which when built up can cause disruption to homeostasis, due to the prod. of ATP
→ CO2 results in relaxing smooth muscle
→ increases blood flow
→ allows more oxygen to spread → restores homeostasis

ALL of this is happening in the muscles being worked out exclusively, and by the local cells.
the blood cells are the control, signal, and effector

examples of Extrinsic Control systems

Low blood pressure is detected by the NERVOUS SYSTEM which alerts the BRAIN to INCREASED HEART RATE by constricting blood vessels, increasing blood pressure, and returning to homeostasis

why: the nervous system (including the brain) are SEPARATE from the circulatory and blood.

What do cells do to help maintain homeostasis

they communicate

What are the Major cell communication methods,
and the specific types within each

DIRECT INTERCELLULAR COMMUNICATION
→ Gap Junction
→ Transient Linkup

INDIRECT INTERCELLULAR COMMUNICATION
→ Paracrine Secretion
→Autocrine Secretion
→Neurotransmitter Secretion

Gap Junction

A multiprotein complex (thousands exist per cell) in which move molecules, ions, and charges (exchange materials cells can sense and use to bring change)

Comm. w/ cells nearby

Transient Linkup

Surface epitopes / bulges that interact with SPECIFIC cells that match

Paracrine Secretion

Cells secrete signals (paracrine) that bind to target receptors
Does not need to be next door, just local

Autocrine Secretion

cell releases signal to itself
(receptor and signal on the same cell)

Neurotransmitter Secretion

Neuron releases a signal to local target cells

Endocrine Signaling

Large Scale
Endocrine cells release hormones into the blood which travel “abroad” throughout the whole body

Hormone

Extracellular signalling released into the blood

→ acts as a receptor in distal tissue to ellicit a physio response
→ only specific targets can respond

neurohormone

hormone released by a neuron

are neurohormones hormones?
Are hormones neurohormones?

all neuro are hormone
not all hormone are neuro

Nervous vs Endocrine system Key points

Nervous
- Fact Acting (millisecond)
- Short Lasting
- Broad
- Short Distance (?)
- Neurotransmitters to synaptic cleft
-Wired

Endocrine
- Slow Response hormones
- Long Lasting
- Specific target
- Long Distance (?)
- Hormone to Blood

What does Positive Feedback do

– Amplifies the initial change
– Moves the system away from the set range (temporarily)

Positive feedback is the amplification of a body's response to a stimulus

It is a CYCLE
Example: cattle start running, which causes more to panic, which cause more to run, which causes more to panic…

Does Positive feedback effect Homeostasis

No

Example of Positive Feedback

Child Birth

why:

→We always have estrogen and oxytocin (in blood) by default
→ If we need more, we get more
→ During Birth, estrogen from ovaries induces oxytocin in uterus
→ Oxytocin stimulates the placenta to make lipids
→ causes contractions → more oxytocin → faster birth

What Ends Positive Feedback

the stimulus ends

Feedforward Mechanism characteristics

Operate W/O Detectors
Activate homeostasis mechanisms and anticipate the changes

Feedforward mechanism examples

respond to an anticipated event (like graduation, a wedding, going swimming) → must be PLANNED

Or ‘body rhythms’ where our body anticipated based on routine
(waking up at X time regularly, bathroom schedule, knowing the way home)

Our body set range / homeostasis can change when…

Sick (fever)
Age Up (BMR)
Thru-out the day (Circadian Rhytm)

If we deal with an unexpected stimulus, what happens

we are discombobulated

ex: we wake up before we expect, feel like shit

Do feedforward systems impact homeostasis? How

Yes

The body PREPARES the body for the anticipated changes