Biology Term 2 Homeostatis and Infectious Disease

Homeostasis

The body’s ability to maintain a stable internal environment in the face of a constantly changing external environment.

Detect and Effect

Use the nervous and endocrine system in Homeostasis

Cause and Effect example

Low/high CO2 or O2

Exteroreceptors

detect external stimuli, located close to the surface

Interoreceptors

detect internal state

Visceral

related to internal organs, particularly those in the abdominal cavity.

Chemoreceptors

a type of receptor that detects chemical stimuli, such as taste and smell, and is involved in monitoring changes in the internal environment.

Chemoreceptor examples

taste, smell, hormones, pheromones

Pheremones

chemical signals released by organisms to communicate with others of the same species, often related to mating or territory.

Thermoreceptors

specialized receptors that detect changes in temperature and help maintain body temperature homeostasis.

Photoreceptors

specialized cells in the retina that detect light and enable vision.

Mechanoreceptors

specialized sensory receptors that respond to mechanical pressure or distortion, playing a crucial role in the sense of touch and proprioception.

Nociceptors

specialized sensory receptors that detect painful stimuli and are involved in the perception of pain.

Detection comes from

Different receptors

Correction happens when

Disturbance is detectedand mechanisms are activated to restore balance.

Positive and Negative Feedback

Provide a response

Muscles

Contract in response to neural stimuli

Glands

Produce secretion

Glands can produce

Hormones

Hormones role

travel to and stimulate a response in other cells

Negative feedback loops

Keep internal environment as stable as possible, gets the body to dynamic equilibrium

Dynamic equilibrium

A state of balance in the body's internal environment, maintained through various physiological processes.

Positive feedback loop

Pushes internal environment to keep escalating response, amplifies the intial response to keep it going

Negative feedback mechanisms

Involves. aresponse that reverses the change detected

Receptor

detects change

effector

activated to induce an opposite effect

Positive feedback mechanisms

Amplification of a response

Positive feedback example

Breastfeeding>prolactin

prolactin

A hormone that stimulates milk production for women.

Metabolic rates and conditions

efficiency of the corrective mechanisms are reliant on this

Anabolic reactions

builds larger complex molecules from smaller smaller molecules

Catabolic reactions

breakdown larger molecules to release smaller molecules

Metabolism

The complete range of chemical reactions that occur within a living organism

Optimal levels

conditions under which an enzyme (and organisms) function best

Tolerance range

The range of environmental conditions under which an enzyme or organism can function or survive

Tolerance limits

The minimum and maximum values for conditions within which an enzyme (or organism) can fucntion (or survive)

Irritability

The ability to detect and respond to changes in the environment

Coordination

Occurs when different body parts work together to maintain homeostasis

Sensor

detects the stress

Control center

integrates the messages from sensor and to effector

Effector receives…

message from the control center and produces the response to reestablish homeostasis

PNS

divided into somatic and autonomic, crucial in maintaining many aspects of homeostasis

Cardiovascular system

Controls the rate and strength of the heartbeat and the distribution of blood to different organs by changing the diamters of arteries.

Digestive system

Controls mixing and movement of food through the gut and secretion of digestive enzymes in various regions of the gut.

Respiratory system

Controls the diameter of major airways of lungs and the secretion of mucus over respiratory surfaces

Excretory system

Promotes emptying of the bladder and controls rate of production of urine by the kidneys

Reproductive Syetm

Controls contraction of various parts of the reproductive tract in males and females, and thus the passage of eggs, sperm, and embryos.

Metabolic regulation

Controls the formation and release of hormones affecting overall metabolism

Temperature regulation

Controls cutaneous blood flow and sweating

Eye function

Controls the diameter of the pupil to regulate incoming light, secretion of tears and focusing of the lens

Axon

a single long, thin extension that sends impulses to another neuron

Myelin sheath

a many-layered lipid and protein covering produced by schwann cells

Sensory neurons

carry impulses from tissues and organs to the CNS

Interneurons

interpret impulses, connect neurons with other neurons

Motor neurons

carry impulses from CNS to muscles.

Signal transduction at a molecular level

The process by which a cell responds to external signals through a series of molecular events, leading to a functional response.

Electrical signal

uses positive and negative charges from ions and solutions

Chemical signals

Uses chemical molecules as messengers to pass the signal on

chemical and electrical signals

alternate as signals flow between neurons

Action potential

Electrical signal that travels along the length of a single neuron

Potential relies on

differences in chemical charge on inside and outside of neuron

Potential

the movement of charged particles across membrane

At rest

higher concentration of positive ions outside and negative ions inside

Extracellular

Outside of the neuron cell

Intracellular

Inside of the neuron cell

Neurotransmitters

Transmit the signal across the synapse

AP in pre-synaptic cells

triggers vesicles containing neurotransmitters to undergo exocytosis into the synaptic cleft

pre-synaptic cell