Cell Structure & Function Flashcards
What is cell theory
3 main components:
All organisms are made of cells
Cells are the basic units of life
Cells come from pre existing cells that have multiplied
What is the theory of evolution
It suggests that there is a ‘survival of the fittest’ approach, because the ‘fittest’ organisms - those most suited to their environments are the ones that are able to reproduce most successfully, and are more likely to pass on their traits to the next generation
What are cells?
Cells are the smallest structural and functional unit of the human body. They can specialise.
What happens when a group of specialised cells perform a single job?
It forms a tissue
What happens when a group of tissues carry out a particular function in the body?
Forms an organ
What happens when a group of organs which have related functions come together?
It creates an organ system such as the respiratory system
Discuss the relationship between cells, tissues and organs
We start off as one cell, and end up at around 37 trillion. Cells come together and specialise to form tissue such as muscle tissue. When a group of tissues carry out a particular function in the body, it forms organs, and these organs can come together to form organ systems
cells < tissue < organ < organ systems
What are the 4 different types of tissues?
Epithelial tissue
Connective tissue
Muscle tissue
Nervous tissue
What is epithelial tissue?
This consists of tightly packed sheets of cells which cover surfaces - including outside of the body, and inside the body (such as lining body cavities). For example, outer layer of skin and lining of small intestine
It’s main function is for protection, however, at different parts of the body it could serve different purposes
What is connective tissue?
It is the tissue that connects/separates/ supports(in terms of structure) to all the other types of tissue in the body. It is in between other tissues
It consists of cells surrounded by a fluid called the extracellular matrix, which is made up of protein fibres like collagen and fibrin in a solid, liquid substance
It can also help store fat, help move nutrients and other substances between tissues and organs, and also assists in repairing damaged tissue
What is muscle tissue?
This is composed of cells which have the ability to shortern or contract in order to produce movements of the body part. It is essential for keeping the body upright and for it to move
In other words, it is what enables us to move
What are the 3 main types of muscle tissue
Skeletal
Cardiac
Smooth
What is skeletal muscle tissue?
These are muscle tissues attached to bones by tendons, and allows us to control movements. It is striated (striped muscle)
What is cardiac muscle tissue?
It is only found in the walls of the heart. It is also striated, but it an involuntary muscle tissue
The cardiac muscle is responsible for the contractility of the heart and, therefore, the pumping action. The cardiac muscle must contract with enough force and enough blood to supply the metabolic demands of the entire body.
What is smooth muscle tissue?
It is found in walls of blood vessels, as well as walls of the digestive tract, uterus, urinary bladder. It isn’t striated, and it’s involuntary
The role of the smooth muscles is to control the involuntary movement of most organs present in the body. They provide smooth, steady contractions to enable the movement of substances (i.e. food in the digestive tract)
What is nervous tissue?
It is involved in sensing stimuli - external or internal cues - and processing and transmitting information. It consists mainly of two types of cells; neurons / nerve cells and glia cells.
The nervous system regulates and controls body functions and activity.
What do the neurons do?
They are the basic functional unit of the nervous system, and they generate electrical signals to allow neurons to convey info quickly over long distances
What are examples of different organ systems? (12)
Cardiovascular
Digestive
Skeletal
Lymphatic
Endocrine
Integumentary
Muscular
Nervous
Reproductive
Respiratory
Urinary
Immune
What is the cardiovascular system?
Function is to transport oxygen, nutrients, and other substances to the cells and transports wastes, carbon dioxide, and other substances away from the cells; it can also help stabilize body temperature and pH
What is the digestive system?
Function is to process foods and absorbs nutrients, minerals, vitamins, and water
What is the skeletal system?
Function is to support and protects soft tissues of the body; provide movement at joints; produce blood cells; and stores minerals
What is the lymphatic system?
Function is to defend against infection and disease and transfers lymph between tissues and the blood stream
What is the Endocrine system
Function is to provide communication within the body via hormones and directs long-term change in other organ systems to maintain homeostasis
What is the integumentary system
Function is to provide protection from injury and fluid loss and provides physical defense against infection by microorganisms; involved in temperature control
What is the muscular system
Function is to provide movement, support, and heat production
What is the Nervous system
Function is to collect, transfer, and process information and directs short-term change in other organ systems
What is the reproductive system?
Function is to produce gametes—sex cells—and sex hormones; ultimately produces offspring
What is the respiratory system
Function is to deliver air to sites where gas exchange can occur
What is the urinary system
Function is to remove excess water, salts and waste products from the blood and body and controls pH
What is the immune system
Function is to defend against microbial pathogens - disease causing agents and other diseases
Explain how all the organ systems are interlinked.
All organ systems have to work together to keep the body functioning properly. For example, when exercising, the respiratory system and the circulatory system work closely to deliver oxygen to cells to get rid of the CO2 the cells produce. Only when both systems work together can there be successful gas exchange.
On top of this, at all times, the nervous system also sends messages via neurons to various functions of the organ systems –> systems working together well
What is meant by the scale of the body?
Micro, meso, macro levels
What is meant by the complexity of the body?
All systems are interconencted
What is meant by the dynamic nature of the body?
Multiple processes occurring simultaneously
Describe the anatomical position
It involves a person standing still, facing straight with feet pointed forward, as well as palms towards the front
What are the different body directions we need to know? (10)
Superior
Inferior
Anterior
Posterior
Lateral
Medial
Dorsal
Ventral
Distal
Proximal
What are body directions?
These are terms used to describe various parts of the body with reference to other parts. I.e. the head is superior to the feet
What does superior mean for body directions?
Above (e.g. head is superior to the heart)
What does inferior mean for body directions?
Below (e.g. feet are inferior to the head)
What does Anterior mean for body directions?
Toward the front of the body in the anatomical position (e.g. the nose is anterior to the ears)
What does posterior mean for body directions?
Toward the back of the body (e.g. The ears are posterior to the nose)
What does lateral mean for body directions?
Away from the median plane of the body (e.g. the shoulder is lateral to the head)