BIOL10002 Lecture Notes - Lecture 10: Basal Metabolic Rate, Extracellular Fluid, Elastin
Week 4
Lecture 10
Tissues and Homeostasis
Tissue Types
1. Epithelial Tissue
- Tightly connected cells
- line blood vessels, various tubules & ducts
Functions
- Create barriers between the internal and external environment
- Regulate transport across barriers
- May be involved in secretion and absorption
- May be involved in smell and taste
2. Muscle Cells
- Most abundant tissue in body
Function
- Muscle cells contain long filaments of myosin and actin
- allow muscles to contract and exert force
3. Connective Tissue
- common origin (mesenchyme)
- loose cells are not necessarily static and can be scattered, embedded in a non-living extracellular matrix
composition of ECM different for different connective tissues
ECM protein includes collagen and elastin, secreted by fibroblasts or stroma
Collagen –strong fibres that are resistant to stretch = structural strength for organ
Elastin - long fibres that can be stretched and then recoil
4. Nervous Tissue
Homeostasis
- A stable internal environment of interstitial fluid makes complex multicellular animals possible
- requires control and regulation in response to changes in ext. and int. environment
- Temperature, pH, oxygen, vitamins, hormones
- The regulatory systems are the nervous system and the endocrine system.
Negative Feedback: Reduce or reverse a process
Positive Feedback: Amplify or increase a response beyond set point
Animals are temperature sensitive;
- Ectotherms: body temperature determined by external environment
- Endotherms: regulate their own body temperature by producing heat or mechanism for heat loss
- Metabolism (generates heat in the body)
- Evaporation (helps to release heat from the body)
- Heat from body via blood to skin is lost to the environment
Hypothalamus
- regulates hormones
- senses whether levels are below or above set point
Metabolism: All energy reactions in the body are inefficient and produce heat as a by-product.
Basal metabolic rate (BMR): is the amount of daily energy consumed by humans and other animals at rest
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Document Summary
Line blood vessels, various tubules & ducts. Create barriers between the internal and external environment. May be involved in secretion and absorption. May be involved in smell and taste: muscle cells. Muscle cells contain long filaments of myosin and actin. Allow muscles to contract and exert force: connective tissue. Loose cells are not necessarily static and can be scattered, embedded in a non-living extracellular matrix. Composition of ecm different for different connective tissues. Ecm protein includes collagen and elastin, secreted by fibroblasts or. Collagen strong fibres that are resistant to stretch = structural strength. Elastin - long fibres that can be stretched and then recoil: nervous tissue stroma for organ. A stable internal environment of interstitial fluid makes complex multicellular animals possible. Requires control and regulation in response to changes in ext. and int. environment. The regulatory systems are the nervous system and the endocrine system. Positive feedback: amplify or increase a response beyond set point.
